NOVEL RECEPTOR-TYPE PHOSPHOTYROSINE PHOSPHATASE-SIGMA

Abstract: The present invention relates to a novel receptor-type protein tyrosine phosphatase protein or glycoprotein, term RPTP-sigma (also known as RPTPase-sigma); DNA encoding therefor, a restriction map of cDNA which is shown in the figure, antibodies specific for the protein or glycoprotein, methods for production and identification of the protein or glycoprotein, methods for detection of nucleic acid encoding the protein, and methods for screening compounds capable of binding to and either inhibiting or stimulating RPTP-sigma phosphatase activity.

Description: KOVEL RECEPTOR-TYPE PHOSPHOTYROSZNE PHOSPHATASE -SIGMA 1. INTRODUCTION 5 The present invention, in the field of « biochemistry and cell and molecular biology, relates to a novel receptor-type protein tyrosine phosphatase protein or glycoprotein, termed RPTPσ (also known as RPTPase-σ) , DNA coding therefor, antibodies specific 10 for the protein or glycoprotein, methods for production and identification of the protein, methods for detection of nucleic acid encoding the protein, and methods for screening compounds capable of binding to and either inhibiting or stimulating RPTPσ 15 phosphatase activity. 2. BACKGROUND OF THE INVENTION Tyrosine phosphorylation of proteins is involved in an increasing number of cellular signalling events 2o and is critical for regulation of normal cell growth, proliferation and differentiation. It was originally implicated in signalling by paracrine- or autocrine- acting growth factors, and endocrine hormones such as insulin (see Yarden, Y. et al . , Annu. Rev. Biochem . 25 57:443-478 (1988) for review). It is now clear that this posttranslational modification is also involved in diverse processes such as the activation of cells of the immune system by antigens (Klausner, R.D. et al . , Cell 64:875-878), signalling by lymphokines 30 (Hatakeya a, M. et al . , 1991 Science 252:1523-1528 (1991); Mills, G.B. et al . , J. Biol . Chem . 265:3561- 3567 (1990)), and cellular differentiation and survival (Fu, X.-Y. 1992 Cell 70:323-335; Schlessinger, J. et al . 1992 Neuron 9 : 1-20 ; 3 5 Velazquez, L. et al. , 1992 Cell ' 70:313-322) . Links are also emerging between tyrosine phosphorylation and the processes of cell adhesion and cell-cell contact. The identification of several growth factor receptors and retroviral oncogenes as tyrosine- specific protein kinases indicated that protein phosphorylation on tyrosine residues plays a key role in cellular growth control. This notion is bolstered by the observation that the level of tyrosine phosphorylation of enzymes important in signal transduction (such as phospholipase C) correlates with their increased activity upon growth factor stimulation, thus establishing a functional role for tyrosine phosphorylation (Ullrich, A., et al . , Cell 61:203-212 (1990)). Most of the processes in which tyrosine phosphorylation is implicated involve the transduction of a signal through the cell membrane. This can occur through dimerization-mediated activation of members of the receptor tyrosine kinase family by soluble ligands (reviewed in Ullrich, A. et al . , supra) . However, receptor tyrosine kinase activity is also modulated by membrane-bound ligands on neighboring cells, as in the case of the interaction between the εevenleεε kinase and the bride of εevenless protein (Rubin, G.M. 1991, Trendε in Genet . 7:372-376). The degree and pattern of phosphorylation of tyrosine residues on cellular proteins are regulated by the opposing activities of protein-tyrosine kinases (PTKases; ATP:protein-tyrosine O-phosphotransferase, •EC 2.7.1.112) and protein-tyrosine-phosphatases (PTPases; protein-tyrosine-phosphate phosphohydrolase, EC 3.1.3.48). The structural characteristics and evolution of PTKases as well as their role in the regulation of cell growth have been reviewed (Hunter, T., et al . , Annu . J?ev. Biochem . 54:897-930 (1985); Ullrich, A., et al . , supra) . 2.1. Phosphotyrosine Kinases (PTKsl Tyrosine kinases comprise a discrete family of enzymes having common ancestry with, but major differences from, serine/threonine-specific protein kinases (Hanks, S.K. et al . , (1988) Science 241:42- 52) . The mechanisms leading to changes in activity of tyrosine kinases are best understood for receptor-type tyrosine kinases which have a transmembrane topology (Ullrich, A. et al . , supra) . With such kinases, the binding of specific ligands to the extracellular domain of these enzymes is thought to induce their oligomerization leading to an increase in tyrosine kinase activity and activation of the signal transduction pathways (Ullrich, A. et al . , supra) . The importance of this activity is supported by the knowledge that dysregulation of kinase activity through mutation or over-expression is a mechanism for oncogenic transformation (Hunter, T. et al. , supra ; Ullrich, A. et al . , 1990, supra) . Tyrosine phosphorylation initiated by several receptor tyrosine kinases has been implicated, for example, in neuronal cell proliferation and differentiation (Chao, M.V. (1992) Cell 68:995-997). These include the receptors for neurotrophic factors belonging to the trk family of receptor tyrosine kinases, as well as PDGF and FGF receptor tyrosine kinases (Chao, M.V. (1992) Neuron 9:583-593). It has been demonstrated that there is an association between favorable outcome in human neuroblastoma and high level expression of the tyrosine kinases, (Nakagawara, A. et al. (1993) N England J Med 328:847-854. Virtually nothing is known about the control of tyrosine phosphorylation by protein tyrosine phosphatases in the mammalian nervous system. The existence of receptor-like tyrosine kinases 5 with an extracellular domain similar to cell adhesion molecules of the CAM-family (e.g., Axl and Ark (0 « Bryan, J.P. et al . , 1991 Mol . Cell . Biol . 11:5016- 5031; Rescigno, J. et al. , 1991 Oncogene 6:1909- 1913)) implicates tyrosine phosphorylation as a 0 broadly employed direct, downstream effector mechanism for precise cell-cell recognition and signalling events. Non-receptor type tyrosine kinases are in some cases associated with other proteins having a trans-membrane topology, e . g. , Lck kinase and the CD4 5 protein or Fyn kinase and T-cell receptor complex components (Haughn, L. et al . , 1992 Nature 358:328- 331; Samelson, L.E. et al . , 1992 Proc. Natl . Acad . Sci . USA 87:4358-4362; Veillette, A. et al . , 1988 Cell 55:301-308). However, the mechanism by which kinase o activity is modulated in these instances is not understood. 2.2. Protein Tyrosine Phosphatases CPTPs) The PTPs are composed of at least two very 5 distinct broad categories: the protein serine/threonine phosphatases and the protein tyrosine phosphatases (Hunter, T. Cell, 58:1013-1016 (1989)). In contrast to phosphatases, protein kinases have greater sequence similarity between serine/threonine- 0 specific and tyrosine-specific enzymes. To date, more than 26 PTPs have been identified (Saito, H. et al . (1991) Cell Growth & Differentiat . 2:59-65; Charbonneau, H. et al . (1992) Annu . Rev . Cell Biol . 8:463-493) . The known enzymes can be divided into two 5 groups; a cytosolic form and a receptor-type form with a single transmembrane domain (receptor-type PTP or RPTP) . Most RPTPs contain two conserved catalytic tyrosine phosphatase (PTPase) domains each of which encompasses a segment of 240 amino acid residues (Saito et al., supra; Charbonneau et al., supra). The catalytic domain contains a highly conserved motif of 11 amino acid residues, (I/V)HCXAGXXR(S/T)G (SEQ. ID NO:l), in which the cysteine residue is essential for protein tyrosine phosphatase activity (Streuli, M. et al., (1990) EMBO J. 9:2399-2407; Pot, D. A. et al . (1992) J " . Biol. Chem. 267:140-143; Wang, Y. et al. (1991) EMBO J. 10:3231-3237). The RPTPs can be subclassified into five types based upon the amino acid sequence diversity of their extracellular domains (Fisher et al., supra; Saito et al., supra; Charbonneau et al., supra; Krueger, N.K. et al. (1992) Proc. Natl . Acad. Sci . USA 89:7417-7421; Barnea, G. et al . , (1993) Mol. Cell. Biol. 13:1497- 1506) . Type II RPTPs are characterized by the presence of both immunoglobulin (Ig)-like and fibronectin type III (FNIII)-like repeats in the extracellular domain. Thus, they resemble the N-CAM family of cell adhesion molecules (Cunningham, B.A. et al . , (1987) Science 236:799-806; Barthers, D. et al., (1987) EMBO J. 6:907-914; Edelman, G.M. et al . (1991) Annu. Rev. Biochem. 60:155-190; Grumet, M. (1991) Curr. Opin. Neurobiol. 1:370-376) and may therefore function as cell adhesion molecules. Examples of such RPTPs include LAR (Streuli, M. et al., (1988) J. Exp. Med.168:1523-1530; Yu, Q. et al . , (1992) Oncogene 7:1051-1057; Streuli, M. et al . , (1989) Proc. Natl. Acad. Sci. USA 86:8698-8702), PTPμ (Gebbink, M.F.B.G. et al., (1991) FEBS Lett. 290:123-130) and PTP/ (Jiang, Y.-P. et al . , (1993) Mol . Cell . Biol . 13:2942- 2951 and DPTP (Streuli, M. et al . , (1989), supra) . An analysis of the expression pattern of several RPTPs in the developing Drosophila CNS suggests some function of these molecules in aspects of axon guidance and outgrowth (Tian, S.S. et al . , 1991 Cell 67:675-685; Yang, X. et al . , 1991, Cell 67:661-673), an observation which might be related to the ability of RPTPs to control the activity of src-family tyrosine kinases (Mustelin, T. et al . , 1989, Proc. Natl . Acad . Sci . USA 86:6302-6306; Ostergaard, H.L. et al . , 1989, Proc . Natl . Acad . Sci . USA 86:8959-8963; Zheng, X.M. et al . , 1992, Nature 359:336-339). Certain RPTPs may function as tumor suppressor genes, for example, by controlling contact inhibition (LaForgia, S. et al . , 1991 Proc . Natl . Acad . Sci . USA 88:5036-5040). Elevation of cellular phosphotyrosine may occur through mechanisms other than the activation of a tyrosine kinase itself. For instance, expression of the v-crk oncogene, though not a tyrosine kinase, induces the phosphorylation of tyrosine residues through a poorly understood mechanism (Mayer, B.J. et al . (1988) Nature 332:272-275) . Potentially, such an outcome could result from either mutation of the substrate or through a general decrease in cellular phosphatase activity, especially in view of the normally high turnover rate of cellular tyrosine- phosphate (Sefton, B.M. et al . (1980) Cell 20:807- 816) . The latter possibility is suggested by the demonstration that tyrosine phosphatase inhibitors can "reversibly transform" cells (Klarlund, J.K. Cell 41 : 707-717 (1985)). PTPases could therefor act as recessive oncogeneε. While we are beginning to understand more about the structure and diversity of the PTPases, much remains to be learned about their cellular functions. Thus, a better understanding of, and an ability to control, phosphotyrosine metabolism requires knowledge not only the role of tyrosine kinase activity, but also of the action of PTP family enzymes as well. It is clear in the art that further delineation of structure-function relationships among cytoplasmic and receptor type PTPasses are needed to gain important understanding of the mechanisms of cell growth, differentiation, and oncogenesis. 3. SUMMARY OF THE INVENTION The present invention relates to a novel mammalian receptor-type protein tyrosine phosphatase-σ (RPTPσ) protein or glycoprotein molecule, functionally equivalent derivatives of RPTPσ, and analogs of the RPTPσ. Further, the present invention relates to DNA encoding such RPTPσ proteins and their derivatives and antibodies directed to RPTPσ proteins, and/or RPTPσ functionally equivalent derivatives and RPTPσ analogs. Still further, the present invention relates to methods for the production and identification of RPTPσ proteins, functionally equivalent derivatives, and analogs, methods for detection of nucleic acid encoding the RPTPσ proteins and derivatives, and methods for screening compounds capable of binding to and either inhibiting or stimulating RPTPσ biological activity, e.g.. its enzymatic phosphatase activity. Preferably, the nucleic acid molecule encodes human RPTPσ or encodes a functional derivative thereof. The DNA molecule is preferably cDNA or genomic DNA. The invention is further directed to the DNA molecule in the form of an expression vehicle, as well as prokaryotic and eukaryotic host cells having the DNA molecule. 4. DESCRIPTION OF THE FIGURES FIG. 1 shows a restriction map of rat cDNA clone encoding RPTPσ. The thin lines indicate several overlapping cDNA clones; both strands of each were sequenced. Unfilled area represents the open reading frame for RPTPσ containing the putative signal peptide (S) and transmembrane domain (TM) . The thick lines indicate the 5• and 3' untranslated sequences. Restriction sites are: E (EcoRI) , B (BamHI) , BL (Bglll) , ML(MluI) , S (Stul) , AP (Asp700) , K (Kpn I) , SP (Spl I) . A scale bar in kilobase (kb) is at the top. FIG. 2 (A)-2(G) shows the nucleotide sequence (SEQ ID NO:2) and deduced amino acid sequence (SEQ ID NO:3) of rat RPTPσ. The predicted translation initiation site is indicated by an asterisk. The translation stop site is double-underlined. The predicted signal peptide and transmembrane regions are underlined and two tandem tyrosine phosphatase domains are boxed. Three-letter amino acid code is used. FIG. 3 shows a proposed alignment of three Iglike domains of RPTPσ (SEQ ID NO:3) to the first Ig-like domain of rat LAR (SEQ ID NO:4) (Yu, Q. et al . , (1992) Oncogene 7:1051-1057) and mouse N-CAM (SEQ ID NO:5) (Barthers, D. et al . , (1987) EMBO J . 6:907-914). The residue numbers of the initial and end amino acids of each repeat are indicated at left and right. Conserved residues in these repeats are highlighted in bold. The cysteine residues are indicated by asterisks. FIG. 4 shows a proposed alignment of five fibronectin type III repeats of RPTPσ (SEQ ID NO:3) to the first FN Ill-like repeat of rat LAR (SEQ ID NO:6) (Yu et al . , supra) and to the human fibronectin type III repeat-domain 7 (SEQ ID NO:7) (Kornblihtt, A.R. et al . , (1985) EMBO J . 4:1755-1759). The residue numbers of the initial and end amino acids of each repeat are indicated at the left and right (except for human FNIII-7) . Conserved residues in these repeats are highlighted in bold. FIG. 5 shows a schematic representation of RPTPσ indicating the possible different functional domains. FIG. 6 shows the results of Northern blot analysis of RPTPσ expression in postnatal rat tissues. The blot was hybridized with a cDNA probe encoding amino acid residue 408 to 521 of the extracellular domain of RPTPσ. The RNA size in kilobase (kb) is shown on the left. FIG. 7(A) - 7(D) are a series of micrographs showing results of in situ hybridization analysis of RPTPσ expression in rat. FIG. 7(A) is a sagittal section of whole rat at embryonic day 12 (E 12) was hybridized with labelled M probe-l". ex, cortical neuroepithelium; 4V, 4th ventricle; LV, lateral ventricle; SC, spinal cord; DRG, dorsal root ganglia. FIG. 7(C) is a sagittal section of adult rat brain to which was hybridized labelled probe-1. Cb, cerebellum; p y pyramidal cell layer; GrDG, granular layer of dentate gyrus; OB, olfactory bulb. FIG. 7(B) and 7(D) show tissue sections adjacent to the sections depicted in FIG. 7(A) and FIG. 7(C), respectively, which were hybridized with labelled probe-l in the presence of a 70-fold excess of unlabelled oligomer to demonstrate the specificity of in situ hybridization. FIG. 8 shows transient expression of RPTPσ in human embryonic kidney 293 cells. Panel A shows results of immunoprecipitation and immunoblot of RPTPσ. Cells were transiently transfected with RKsigma or RKSigmaR. Supernatants of lysates were immunoprecipitated with polyclonal FNIII Ab and then immunoblotted with same antibodies. Lane 1, lysate from cells transfected with RKSigma; lane 2, lysate from cells transfected with RKSigmaR. Panel B shows an immunoblot analysis of RPTPσ with polyclonal FNIII Ab. Lane 1 and lane 2 are same as in Panel A. Molecular mass markers are shown in kDa. 5. DETAILED DESCRIPTION OF THE INVENTION 5.1. RPTPσ Through the use of recombinant DNA methods, a novel mammalian receptor-type (transmembrane) protein tyrosine phosphatase (PTPase; EC 3.1.3.48) has been identified and cloned from a rat brain stem cDNA library. In view of its receptor-like structure, and the likelihood that it is part of a family, the protein has been termed, RPTPσ (receptor protein tyrosine phosphatase-σ) . The family is designated herein as the "RPTPσs." The amino acid sequence of the rat RPTPσ is shown in FIG. 2(A)-2(G) (SEQ ID NO:3) . The extracellular segment of rat RPTPσ contains 824 amino acids and is composed of 3 Ig-like and 5 fibronectin type III (FNIII)-like repeats. The 627 amino acid cytoplasmic region of rat RPTPσ consists of two catalytic domains oriented in tandem. In addition to being composed of intracellular domains having enzymatic activity, the receptor family to which RPTPs belong includes transmembrane proteins having and N-terminal extracellular domains, analogous to the tyrosine kinase enzyme family (Tonks, N.K. et al . (1988) Biochemistry 27:8695-8701; Charbonneau, H. et al . (1988) Proc . Natl . Acad. Sci . USA 85:7182-7186; Streuli, M. et al . (1988) J. Exp. Med . 168:1523- 2530; Streuli, M. et al . (1989) Proc . Natl . Acad . Sci . USA 86:8698-8702) . It is concluded, therefore, that ligands in the extracellular environment can control the activity of this membrane-associated subclass of PTPases. The cDNA cloning of rat RPTPσ and the complete DNA and amino acid sequences of rat RPTPσ are described herein in the Working Example presented in Section 6, below. Further, Northern analysis, as demonstrated in the Working Example presented in Section 7, below, has been used to identify the natural expression of RPTPσ in various rat tissues. Briefly, rat RPTPσ is highly expressed in the brain as a 5.7 kb transcript. Rat RPTPσ is also expressed in the lung and intestine as a 6.9 kb transcript but at significantly lower level. Further, RPTPσ is expressed in anatomically distinct regions of rat brain and its expression is developmentally regulated. In situ hybridization studies confirm that RPTPσ is localized predominantly in the nervous system an d can be detected in the rat as early as embryonic day 12 (E12) . During embryonic development, RPTPσ is expressed extensively in the central and peripheral nervous systems, including the trigeminal and dorsal root ganglia as well as retina. In adult rat brain, expression is restricted primarily to the olfactory tubercle, cerebellum, and hippocampus. Within the latter structure, RPTPσ is present in the pyramidal cell layer and the granular layer of dentate gyrus. 5.2. THE RPTPσ CODING SEQUENCE The nucleotide coding sequence* of the rat RPTPσ (SEQ ID N0:2) is depicted in FIG. 2(A)-2(G)). In accordance with the invention, the nucleotide sequence of the RPTPσ protein or its functional equivalent in mammals, including humans, can be used to generate recombinant molecules which direct the expression of RPTPσ; hereinafter, this receptor will be referred to as "RPTPσ", regardless of the species from which it is derived. The invention also relates to RPTPσ genes isolated from other species, including humans, in which RPTPσ activity exists. Such receptors may demonstrate about 80% overall similarity at the amino acid level, and higher, preferably greater than about 95%, homology within specific highly conserved amino acid sequences. A bacteriophage cDNA library may be screened, under conditions of reduced stringency, using a radioactively labeled fragment of the mouse RPTPσ clone. Alternatively the mouse RPTPσ sequence can be used to design degenerate or fully degenerate oligonucleotide probes which can be used as PCR (polymerase chain reaction; Mullis, K. et al . , Cold Spring Harbor Symp. Quant . Biol . 51:263-273 (1986); Erlich, H. et al . , EP 50424, EP 84796, EP 258017, EP 237362; Mullis, K. , EP 201184; Mullis, K. et al . , US 4,683,202; Erlich, H. , US 4,582,788; and Saiki, R. et al . , US 4,683,194) probes or to screen bacteriophage cDNA libraries. A PCR-based strategy may be used to clone human RPTPσ. Two pools of degenerate oligonucleotides, corresponding to a conserved motifs between the rat RPTPσ and known receptor tyrosine phosphatases, may be designed to serve as primers in a PCR reaction. The template for the reaction is cDNA obtained by reverse transcription of mRNA prepared from cell lines or tissue known to express human RPTPσ. The PCR product may be subcloned and sequenced to insure that the amplified sequences represent the RPTPσ sequences. The PCR fragment may be used to isolate a full length RPTPσ cDNA clone by radioactively labeling the amplified fragment and screening a bacteriophage cDNA library. Alternatively, the labeled fragment may be used to screen a genomic library. For a review of cloning strategies which may be used, see e.g.. Maniatis, 1989, Molecular Cloning, A Laboratory Manual, Cold Springs Harbor Press, N.Y.; and Ausubel et al., 1989, Current Protocols in Molecular Biology, (Green Publishing Associates and Wiley Interscience, N.Y.) In accordance with the invention, RPTPσ nucleotide sequences which encode RPTPσ, peptide fragments of RPTPσ, RPTPσ fusion proteins or functional equivalents thereof may be used to generate recombinant DNA molecules that direct the expression of RPTPσ protein or a functionally equivalent thereof, in appropriate host cells. Alternatively, nucleotide sequences which hybridize to portions of the RPTPσ sequence may also be used in nucleic acid hybridization assays. Southern and Northern blot analyses, etc. Due to the inherent degeneracy of the genetic code, other DNA sequences which encode substantially the same or a functionally equivalent amino acid sequence, may be used in the practice of the invention for the cloning and expression of the RPTPσ protein. Such DNA sequences include those which are capable of hybridizing to the murine RPTPσ sequence under stringent conditions. Altered DNA sequences which may be used in accor- dance with the invention include deletions, additions or substitutions of different nucleotide residues resulting in a sequence that encodes the same or a functionally equivalent gene product. The gene product itself may contain deletions, additions or substitutions of amino acid residues within the RPTPσ sequence, which result in a silent change thus produ- cing a functionally equivalent RPTPσ. Such amino acid substitutions may be made on the basis of similarity in polarity, charge, solubility, hydrophobicity, hydrophilicity, and/or the amphipathic nature of the residues involved. For example, negatively charged amino acids include aspartic acid and glutamic acid; positively charged amino acids include lysine and arginine; amino acids with uncharged polar head groups having similar hydrophilicity values include the following: leucine, isoleucine, valine; glycine; asparagine, glutamine; serine, threonine; phenylalanine, tyrosine. As used herein, a functionally equivalent RPTPσ may refer to a receptor which exhibits substantially similar biological activity, e.g.. is a phosphatase capable of binding to the same or similar ligands as RPTPσ, but not necessarily with the same affinity as native RPTPσ, or, for example, may refer to a structurally similar receptor molecule to which an antibody, preferably a monoclonal antibody, specific to an RPTPσ-family-specific epitope. The DNA sequences of the invention may be engi¬ neered in order to alter the RPTPσ coding sequence for a variety of ends including but not limited to altera¬ tions which modify processing and expression of the gene product. For example, mutations may be intro¬ duced using techniques which are well known in the art, e.g. site-directed mutagenesis, to insert new restriction sites, to alter glycosylation patterns, phosphorylation, etc. For example, in certain expression systems such as yeast, host cells may over glycosylate the gene product. When using such expres¬ sion systems it may be preferable to alter the RPTPσ coding sequence to eliminate any N-linked glycosyla¬ tion site. In another embodiment of the invention, the RPTPσ or a modified RPTPσ sequence may be ligated to a heterologous sequence to encode a fusion protein. For example, for screening of peptide libraries it may be useful to encode a chimeric RPTPσ protein expressing a heterologous epitope that is recognized by a commercially available antibody. A fusion protein may also be engineered to contain a cleavage site located between the RPTPσ sequence and the heterologous protein sequence, so that the RPTPσ can be cleaved away from the heterologous moiety. In an alternate embodiment of the invention, the coding sequence of RPTPσ could be synthesized in whole or in part, using chemical methods well known in the art. See, for example, Caruthers, et al., 1980, Nuc. Acids Res. Symp. Ser. 7:215-233; Crea and Horn, 180, Nuc. Acids Res. 9(10):2331; Matteucci and Caruthers, 1980, Tetrahedron Letters 21:719; and Chow and Kempe, 1981, Nuc. Acids Res. 9(12) :2807-2817. Alternatively, the protein itself could be produced using chemical methods to synthesize the RPTPσ amino acid sequence in whole or in part. For example, peptides can be synthesized by solid phase techniques, cleaved from the resin, and purified by preparative high perform¬ ance liquid chromatography. (E.g. , see Creighton, 1983, Proteins Structures And Molecular Principles, W.H. Freeman and Co., N.Y. pp. 50-60). The composi¬ tion of the synthetic peptides may be confirmed by amino acid analysis or sequencing (e.g.. the Edman degradation procedure; see Creighton, 1983, Proteins, Structures and Molecular Principles, W.H. Freeman and Co., N.Y., pp. 34-49. 5.3. EXPRESSION OF RPTPσ AND GENERATION OF CELL LINES THAT EXPRESS RPTPσ In order to express a biologically active RPTPσ, the nucleotide sequence coding for RPTPσ, or a func¬ tional equivalent as described in Section 5.1 supra. may be inserted into an appropriate expression vector, i.e.. a vector which contains the necessary elements for the transcription and translation of the inserted coding sequence. The RPTPσ gene products as well as host cells or cell lines transfected or transformed with recombinant RPTPσ expression vectors can be used for a variety of purposes. These include but are not limited to generating antibodies (i.e.. monoclonal or polyclonal) that bind to the receptor, including those that may be capable of competitively inhibiting the binding of RPTPσ ligands to the native RPTPσ, and would thus "neutralize" activity of RPTPσ, and the screening and selection of RPTPσ ligand analogs or drugs that act via the RPTPσ receptor; etc. 5.3.1. EXPRESSION SYSTEMS Methods which are well known to those skilled in the art can be used to construct expression vectors containing the RPTPσ coding sequence and appropriate transcriptional/translational control signals. These methods include in vitro recombinant DNA techniques, synthetic techniques and in vivo recombination/genetic recombination. See, for example, the techniques described in Maniatis et al., 1989, Molecular Cloning A Laboratory Manual, Cold Spring Harbor Laboratory, N.Y. and Ausubel et al., 1989, Current Protocols in Molecular Biology, Greene Publishing Associates and Wiley Interscience, N.Y. A variety of host-expression vector systems may be utilized to express the RPTPσ coding sequence. These include but are not limited to microorganisms such as bacteria transformed with recombinant bacteriophage DNA, plasmid DNA or cosmid DNA expres¬ sion vectors containing the RPTPσ coding sequence; yeast transformed with recombinant yeast expression vectors containing the RPTPσ coding sequence; insect cell systems infected with recombinant virus expres¬ sion vectors (e.g.. baculovirus) containing the RPTPσ coding sequence; plant cell systems infected with recombinant virus expression vectors (e.g.. cauliflower mosaic virus, CaMV; tobacco mosaic virus, TMV) or transformed with recombinant plasmid expres¬ sion vectors (e.g.. Ti plasmid) containing the RPTPσ coding sequence; or animal cell systems infected with recombinant virus expression vectors (e.g.. adenovirus, vaccinia virus) including cell lines engineered to contain multiple copies of the RPTPσ DNA either stably amplified (CHO/dhfr) or unstably amplified in double-minute chromosomes (e.g.. murine cell lines) . The expression elements of these systems vary in their strength and specificities. Depending on the host/vector system utilized, any of a number of suitable transcription and translation elements, including constitutive and inducible promoters, may be used in the expression vector. For example, when cloning in bacterial systems, inducible promoters such as pL of bacteriophage λ, plac, ptrp, ptac (ptrp-lac hybrid promoter) and the like may be used; when cloning in insect cell systems, promoters such as the baculovirus polyhedrin promoter may be used; when cloning in plant cell systems, promoters derived from the genome of plant cells (e.g.. heat shock promoters; the promoter for the small subunit of RUBISCO; the promoter for the chlorophyll a/b binding protein) or from plant viruses (e.g. , the 35S RNA promoter of CaMV; the coat protein promoter of TMV) may be used; when cloning in mammalian cell systems, promoters derived from the genome of mammalian cells (e.g. , metallothionein promoter) or from mammalian viruses (e.g.. the adenovirus late promoter; the vaccinia virus 7.5K promoter) may be used; when generating cell lines that contain multiple copies of the RPTPσ DNA SV40-, BPV- and EBV-based vectors may be used with an appropriate selectable marker. In bacterial systems a number of expression vectors may be advantageously selected depending upon the use intended for the RPTPσ expressed. For example, when large quantities of RPTPσ are to be produced for the generation of antibodies or to screen peptide libraries, vectors which direct the expression of high levels of fusion protein products that are readily purified may be desirable. Such vectors include but are not limited to the J . coli expression vector pUR278 (Ruther et al. , 1983, EMBO J. 2:1791), in which the RPTPσ coding sequence may be ligated into the vector in frame with the lac Z coding region so that a hybrid AS-lac Z protein is produced; pIN vectors (Inouye & Inouye, 1985, Nucleic acids Res. 13:3101-3109; Van Heeke & Schuster, 1989, J. Biol. Chem. 264:5503-5509); and the like. pGEX vectors may also be used to express foreign polypeptides as fusion proteins with glutathione S-transferase (GST) . In general, such fusion proteins are soluble and can easily be purified from lysed cells by adsorption to glutathione-agarose beads followed by elution in the presence of free glutathione. The pGEX vectors are designed to include thrombin or factor Xa protease cleavage sites so that the cloned polypeptide of interest can be released from the GST moiety. In yeast, a number of vectors containing constitutive or inducible promoters may be used. For a review see, Current Protocols in Molecular Biology, Vol. 2, 1988, Ed. Ausubel et al., Greene Publish. Assoc. & Wiley Interscience, Ch. 13; Grant et al., 1987, Expression and Secretion Vectors for Yeast, .in Methods in Enzymology, Eds. Wu & Grossman, 1987, Acad. Press, N.Y., Vol. 153, pp. 516-544; Glover, 1986, DNA Cloning, Vol. II, IRL Press, Wash., D.C., Ch. 3; and Bitter, 1987, Heterologous Gene Expression in Yeast, Methods in Enzymology, Eds. Berger & Kimmel, Acad. Press, N.Y., Vol. 152, pp. 673-684; and The Molecular Biology of the Yeast Saccharomyces, 1982, Eds. Strathern et al.. Cold Spring Harbor Press, Vols. I and II. In cases where plant expression vectors are used, the expression of the RPTPσ coding sequence may be driven by any of a number of promoters. For example, viral promoters such as the 35S RNA and 19S RNA promoters of CaMV (Brisson et al., 1984, Nature 310:511-514) , or the coat protein promoter of TMV (Takamatsu et al., 1987, EMBO J. 6:307-311) may be used; alternatively, plant promoters such as the small subunit of RUBISCO (Coruzzi et al., 1984, EMBO J. 3:1671-1680; Broglie et al., 1984, Science 224:838- 843); or heat shock promoters, e.g.. soybean hspl7.5-E or hspl7.3-B (Gurley et al., 1986, Mol. Cell. Biol. 6:559-565) may be used. These constructs can be introduced into plant cells using Ti plasmids, Ri plasmids, plant virus vectors, direct DNA transfor¬ mation, microinjection, electroporation, etc. For reviews of such techniques see, for example, Weissbach & Weissbach, 1988, Methods for Plant Molecular Biology, Academic Press, NY, Section VIII, pp. 421- 463; and Grierson & Corey, 1988, Plant Molecular Biology, 2d Ed., Blackie, London, Ch. 7-9. An alternative expression system which could be used to express RPTPσ is an insect system. In one such system, Autographa californica nuclear polyhidrosis virus (AcNPV) is used as a vector to express foreign genes. The virus grows in Spodoptera frugjperda cells. The RPTPσ coding sequence may be cloned into non-essential regions (for example the polyhedrin gene) of the virus and placed under control of an AcNPV promoter (for example the polyhedrin promoter) . Successful insertion of the RPTPσ coding sequence will result in inactivation of the polyhedrin gene and production of non-occluded recombinant virus (i.e. , virus lacking the proteinaceous coat coded for by the polyhedrin gene) . These recombinant viruses are then used to infect Spodoptera frugjperda cells in which the inserted gene is expressed. (E.g.. see Smith et al., 1983, J. Viol. 46:584; Smith, U.S. Patent No. 4,215,051). In mammalian host cells, a number of viral based expression systems may be utilized. In cases where an adenovirus is used as an expression vector, the RPTPσ coding sequence may be ligated to an adenovirus transcription/translation control complex, e.g.. the late promoter and tripartite leader sequence. This chimeric gene may then be inserted in the adenovirus genome by in vitro or in vivo recombination. Inser¬ tion in a non-essential region of the viral genome (e.g. , region El or E3) will result in a recombinant virus that is viable and capable of expressing RPTPσ in infected hosts. (E.g.. See Logan & Shenk, 1984, Proc. Natl. Acad. Sci. (USA) 81:3655-3659). Alterna¬ tively, the vaccinia 7.5K promoter may be used. (See, e.g.. Mackett et al., 1982, Proc. Natl. Acad. Sci. (USA) 79:7415-7419; Mackett et al. , 1984, J. Virol. 49:857-864; Panicali et al., 1982, Proc. Natl. Acad. Sci. 79:4927-4931). Specific initiation signals may also be required for efficient translation of inserted RPTPσ coding sequences. These signals include the ATG initiation codon and adjacent sequences. In cases where the entire RPTPσ gene, including its own initiation codon and adjacent sequences, is inserted into the appro¬ priate expression vector, no additional translational control signals may be needed. However, in cases where only a portion of the RPTPσ coding sequence is inserted, exogenous translational control signals, including the ATG initiation codon, must be provided. Furthermore, the initiation codon must be in phase with the reading frame of the RPTPσ coding sequence to ensure translation of the entire insert. These exogenous translational control signals and initiation codons can be of a variety of origins, both natural and synthetic. The efficiency of expression may be enhanced by the inclusion of appropriate transcription enhancer elements, transcription terminators, etc. (see Bittner et al., 1987, Methods in Enzymol. 153:516-544) .. In addition, a host cell strain may be chosen which modulates the expression of the inserted sequences, or modifies and processes the gene product in the specific fashion desired. Such modifications (e.g.. glycosylation) and processing (e.g.. cleavage) of protein products may be important for the function of the protein. Different host cells have charac- teristic and specific mechanisms for the post-transla- tional processing and modification of proteins. Appropriate cells lines or host systems can be chosen to ensure the correct modification and processing of the foreign protein expressed. To this end, eukaryotic host cells which possess the cellular machinery for proper processing of the primary transcript, glycosylation, and phosphorylation of the gene product may be used. Such mammalian host cells include but are not limited to CHO, VERO, BHK, HeLa, COS, MDCK, 293, WI38, etc. For long-term, high-yield production of recombi¬ nant proteins, stable expression is preferred. For example, cell lines which stably express the RPTPσ may be engineered. Rather than using expression vectors which contain viral origins of replication, host cells can be transformed with the RPTPσ DNA controlled by appropriate expression control elements (e.g. r promoter, enhancer, sequences, transcription termina¬ tors, polyadenylation sites, etc.), and a selectable marker. Following the introduction of foreign DNA, engineered cells may be allowed to grow for 1-2 days in an enriched media, and then are switched to a selective media. The selectable marker in the recombinant plasmid confers resistance to the selection and allows cells to stably integrate the plasmid into their chromosomes and grow to form foci which in turn can be cloned and expanded into cell lines. This method may advantageously be used to engineer cell lines which express the RPTPσ on the cell surface, and which respond to RPTPσ ligand- mediated signal transduction. Such engineered cell lines are particularly useful in screening RPTPσ ligand analogs. A number of selection systems may be used, including but not limited to the herpes simplex virus thymidine kinase (Wigler, et al. , 1977, Cell 11:223), hypoxanthine-guanine phosphoribosyltransferase (Szybalski & Szybalski, 1962, Proc. Natl. Acad. Sci. USA 48:2026) , and adenine phosphoribosyltransferase (Lowy, et al., 1980, Cell 22:817) genes can be employed in tk", hgprt " or aprt " cells, respectively. Also, antimetabolite resistance can be used as the basis of selection for dhfr, which confers resistance to methotrexate (Wigler, et al., 1980, Natl. Acad. Sci. USA 77:3567; O'Hare, et al. , 1981, Proc. Natl. Acad. Sci. USA 78:1527); gpt, which confers resistance to mycophenolic acid (Mulligan & Berg, 1981), Proc. Natl. Acad. Sci. USA 78:2072); neo, which confers resistance to the aminoglycoside G-418 (Colberre- Garapin, et al., 1981, J. Mol. Biol. 150:1); and hygro, which confers resistance to hygromycin (Santerre, et al., 1984, Gene 30:147) genes. Additional selectable genes have been described, namely trpB, which allows cells to utilize indole in place of tryptophan; hisD, which allows cells to utilize histinol in place of histidine (Hartman & Mulligan, 1988, Proc. Natl. Acad. Sci. USA 85:8047); and ODC (ornithine decarboxylase) which confers resistance to the ornithine decarboxylase inhibitor, 2-(difluoromethyl)-DL-ornithine, DFMO (McConlogue L. , 1987, In: Current Communications in Molecular Biology, Cold Spring Harbor Laboratory ed.). 5.3.2. IDENTIFICATION OF TRANSFECTANTS OR TRANSFORMANTS THAT EXPRESS THE RPTPσ The host cells which contain the coding sequence and which express the biologically active gene product may be identified by at least four general approaches; (a) DNA-DNA or DNA-RNA hybridization; (b) the presence or absence of "marker" gene functions; (c) assessing the level of transcription as measured by the expres¬ sion of RPTPσ mRNA transcripts in the host cell; and (d) detection of the gene product as measured by immunoassay or by its biological activity. In the first approach, the presence of the RPTPσ coding sequence inserted in the expression vector can be detected by DNA-DNA or DNA-RNA hybridization using probes comprising nucleotide sequences that are homologous to the RPTPσ coding sequence, respectively, or portions or derivatives thereof. In the second approach, the recombinant expres¬ sion vector/host system can be identified and selected based upon the presence or absence of certain "marker" gene functions (e.g. , thymidine kinase activity, resistance to antibiotics, resistance to methotrexate, transformation phenotype, occlusion body formation in baculovirus, etc.). For example, if the RPTPσ coding sequence is inserted within a marker gene sequence of the vector, recombinants containing the RPTPσ coding sequence can be identified by the absence of the marker gene function. Alternatively, a marker gene can be placed in tandem with the RPTPσ sequence under the control of the same or different promoter used to control the expression of the RPTPσ coding sequence. Expression of the marker in response to induction or selection indicates expression of the RPTPσ coding sequence. In the third approach, transcriptional activity for the RPTPσ coding region can be assessed by hybridization assays. For example, RNA can be isolated and analyzed by Northern blot using a probe homologous to the RPTPσ coding sequence or particular portions thereof. Alternatively, total nucleic acids of the host cell may be extracted and assayed for hybridization to such probes. In the fourth approach, the expression of the RPTPσ protein product can be assessed immunologically, for example by Western blots, immunoassays such as radioimmuno-precipitation, enzyme-linked immunoassays and the like. The ultimate test of the success of the expression system, however, involves the detection of the biologically active RPTPσ gene product. A number of assays can be used to detect receptor activity including but not limited to RPTPσ ligand binding assays; and RPTPσ biological assays using engineered cell lines as the test substrate. 5.3.3 RPTPQΓ ANALOGS RPTPσ analogs, i.e.. RPTPσ molecules which contain additional chemical moieties not normally a part of the peptide, are also intended to be included within the scope of the present invention. Covalent modifications of the RPTPσ protein or of a peptide derived therefrom, for example, may be introduced into the molecule by reacting targeted amino acid residues of the peptide with an organic derivatizing agent that is capable of reacting with selected side chains or terminal residues. Cysteinyl residues most commonly are reacted with alpha-haloacetates (and corresponding, amines) , such as chloroacetic acid or chloroacetamide, to give carboxymethyl or carboxyamidomethyl derivatives. Cysteinyl residues also are derivatized by reaction with bromotrifluoroacetone, α-bromo-/5-(5- imidozoyl)propionic acid, chloroacetyl phosphate, N- alkylmaleimides, 3-nitro-2-pyridyl disulfide, methyl 2-pyridyl disulfide, p-chloromercuribenzoate, 2- chloromercuri-4- nitrophenol, or chloro-7-nitrobenzo- 2-oxa-l,3-diazole. Histidyl residues are derivatized by reaction with diethylprocarbonate, pH 5.5-7.0, because this agent is relatively specific for the histidyl side chain. Para-bromophenacyl bromide also is useful; the reaction is preferably performed in 0.1 M sodium cacodylate at pH 6.0. Lysinyl and amino terminal residues are reacted with succinic or other carboxylic acid anhydrides. Derivatization with these agents has the effect of reversing the charge of the lysinyl residues. Other suitable reagents for derivatizing α-amino-containing residues include imidoesters such as methyl picolinimidate; pyridoxal phosphate; pyridoxal; chloroborohydride; trinitrobenzenesulfonic acid; O- methylisourea; 2,4 pentanedione; and transaminase- catalyzed reaction with glyoxylate. Arginyl residues are modified by reaction with one or several conventional reagents, among them phenylglyoxal, 2,3- butanedione, 1,2-cyclohexanedione, and ninhydrin. Derivatization of arginine residues requires that the reaction be performed in alkaline conditions because of the high pK, of the guanidine functional group. Furthermore, these reagents may react with the groups of lysine as well as the arginine £-amino group. The specific modification of tyrosyl residues per se has been studied extensively, with particular interest in introducing spectral labels into tyrosyl residues by reaction with aromatic diazonium compounds or tetranitromethane. Most commonly, N-acetylimidizol and tetranitromethane are used to form O-acetyl tyrosyl species and 3-nitro derivatives, respectively. Carboxyl side groups (aspartyl or glutamyl) are selectively modified by reaction with carbodiimides (R'-N-C-N-R 1 ) such as l-cyclohexyl-3-(2-morpholinyl- (4-ethyl) carbodiimide or l-ethyl-3-(4-azonia-4,4- dimethylpentyl) carbodiimide. Furthermore, aspartyl and glutamyl residues are converted to asparaginyl and glutaminyl residues by reaction with ammonium ions. Glutaminyl and asparaginyl residues may be deamidated to the corresponding glutamyl and aspartyl residues, under mildly acidic conditions. Either form of these residues falls within the scope of this invention. Derivatization with bifunctional agents is useful for cross-linking the protein or peptide to a water- insoluble support matrix or to other macromolecular carriers. Commonly used cross-linking agents include, e .g. , l,l-bis(diazoacetyl)-2-phenylethane, glutaraldehyde, N-hydroxysuccinimide esters, for example, esters with 4-azidosalicylic acid, homobifunctional imidoesters, including disuccinimidyl esters such as 3,3*- dithiobis(succinimidyl- propionate) , and bifunctional maleimides such as bis- N-maleimido-l,8-octane. Derivatizing agents such as methyl-3-[ (p-azidophenyl)dithio]propioimidate yield photoactivatable intermediates that are capable of forming crosslinks in the presence of light. Alternatively, reactive water-insoluble matrices such as cyanogen bromide-activated carbohydrates and the reactive substrates described in U.S. Patent Nos. 3,969,287; 3,691,016; 4,195,128; 4,247,642; 4,229,537; and 4,330,440 are employed for protein immobilization. Other modifications include hydroxylation of proline and lysine, phosphorylation of hydroxyl groups of seryl or threonyl residues, methylation of the X- a ino groups of lysine, arginine, and histidine side chains (T.E. Creighton, PROTEINS : STRUCTURE AND MOLECULE PROPERTIES , W.H. Freeman & Co., San Francisco, pp. 79-86 (1983)), acetylation of the N- terminal amine, and, in some instances, amidation of the C-terminal carboxyl groups. Such derivatized moieties may improve the solubility, absorption, biological half life, and the like. The moieties may alternatively eliminate or attenuate any undesirable side effect of the protein and the like. Moieties capable of mediating such effects are disclosed, for example, in .REMINGTON' S PHARMACEUTICAL SCIENCES , 18th ed. , Mack Publishing Co., Easton, PA (1990). 5.4 RPTPσ ANTIBODY PRODUCTION AND SCREENING Various procedures known in the art may be used for the production of antibodies to epitopes of the recombinantly produced RPTPσ. Such antibodies include but are not limited to polyclonal, monoclonal, chimeric, single chain, Fab fragments and fragments produced by an Fab expression library. Neutralizing antibodies i.e. , those which compete for the RPTPσ ligand binding sites of the RPTPσ molecule are especially preferred for diagnostics and therapeutics. For example, with respect to diagnostics, disorders involving an abnormal level of RPTPσ protein levels may be recognized by the utilization of such antibodies. These disorders may include, but are not limited to, oncogenic disorders associated with an abnormally high net level of kinase activity, such as is seen in human neuroblastomas (Nakagawara, A. et al. (1993) N England J Med 328:847-854. The antibodies (or fragments thereof) useful in the present invention may be employed histologically, as in immunofluorescence or immunoelectron microscopy, for in εitu detection of RPTPσ. In εitu detection may be accomplished by removing a histological specimen from a subject, and providing a labeled antibody or antibody fragment of the present invention to such a specimen, preferably by applying or overlaying the antibody over the specimen. Through the use of such a procedure, it is possible to determine not only the presence of RPTPσ but also its distribution in the examined tissue. Using the present invention, those of ordinary skill will readily perceive that any of a wide variety of histological methods (such as staining procedures) can be modified in order to achieve such in εitu detection. Such assays for RPTPσ typically comprise incubating a biological sample, such as a biological fluid, a tissue extract, freshly harvested cells, or cells which have been incubated in tissue culture, in the presence of a detectably labeled antibody specific for RPTPσ, and detecting the antibody by any of a number of techniques well-known in the art. The biological sample may be incubated with a solid phase support or carrier such as nitrocellulose, or other solid support which is capable of immobilizing cells, cell particles or soluble pro¬ teins. The support may then be washed with suitable buffers followed by treatment with the detectably labeled RPTPσ-specific antibody. The solid phase support may then be washed with the buffer a second time to remove unbound antibody. The amount of bound label on said solid support may then be detected by conventional means. By "solid phase support" is intended any support capable of binding antigen or antibodies. Well-known supports or carriers include glass, polystyrene, polypropylene, polyethylene, dextran, nylon, amylases, natural and modified celluloses, polyacrylamides, and magnetite. The preferred carrier is totally insoluble in the solution in which the assay of the present invention takes place; partially soluble carriers well-known in the art may also be used. The support material may have virtually any possible structural configuration so long as the support-coupled molecule is capable of binding to an antigen or antibody. Thus, the support configuration may be spherical, as in a bead, or cylindrical, as in the inside surface of a test tube, or the external surface of a rod. Alternatively, the surface may be flat such as a sheet, test strip, etc. Preferred supports include polystyrene beads. Those skilled in the art will know many other suitable carriers for binding antibody or antigen, or will be able to ascertain the same by use of routine experimentation. The binding activity of a given lot of anti-RPTPσ antibody may be determined according to well-known methods. Those skilled in the art will be able to determine operative and optimal assay conditions for each determination by employing routine experimentation. One of the ways in which the RPTPσ-specific anti¬ body can be detectably labeled is by linking the antibody, or a second antibody which binds to the anti-RPTPσ antibody, to an enzyme and use in an enzyme immunoassay (EIA) . This enzyme, in turn, when later exposed to an appropriate substrate, will react with the substrate in such a manner as to produce a chemical moiety which can be detected, for example, by spectrophotometric, fluorimetric or by visual means. Enzymes which can be used to detectably label the antibody include, but are not limited to, malate dehydrogenase, staphylococcal nuclease, delta-5- steroid isomerase, yeast alcohol dehydrogenase, alpha- glycerophosphate dehydrogenase, triose phosphate isomerase, horseradish peroxidase, alkaline phosphatase, asparaginase, glucose oxidase, beta- galactosidase, ribonuclease, urease, catalase, glucose-6-phosphate dehydrogenase, glucoamylase and acetylcholinesterase. The detection can be accomplished by colorimetric methods which employ a chromogenic substrate for the enzyme. Detection may also be accomplished by visual comparison of the extent of enzymatic reaction of a substrate in comparison with similarly prepared standards. Detection may be accomplished using any of a variety of other immunoassays. For example, by radioactively labeling the antibodies or antibody fragments, it is possible to detect RPTPσ through the use of a radioimmunoassay (RIA) (see, for example, Work, T.S. et al . , LABORATORY TECHNIQUES AND BIOCHEMISTRY IN MOLECULAR BIOLOGY, North Holland Publishing Company, New York, 1978, which is incorporated by reference herein) . The radioactive isotope can be detected by such means as the use of a gamma counter or a scintillation counter or by autoradiography. It is also possible to label the antibody with a fluorescent compound. When the fluorescently labeled antibody is exposed to light of the-proper wave length, its presence can then be detected due to fluorescence. Among the most commonly used fluorescent labelling compounds are fluorescein isothiocyanate, rhodamine, phycoerythrin, phycocyanin, allophycocyanin, o- phthaldehyde and fluorescamine. The antibody can also be detectably labeled using fluorescence emitting metals such as l52 Eu, or others of the lanthanide series. These metals can be attached to the antibody using such metal chelating groups as diethylenetriaminepentaacetic acid (DTPA) or ethylenediaminetetraacetic acid (EDTA) . The antibody also can be detectably labeled by coupling it to a chemiluminescent compound. The presence of the chemiluminescent-tagged antibody is then determined by detecting the presence of luminescence that arises during the course of a chemical reaction. Examples of particularly useful chemiluminescent labeling compounds are luminol, isoluminol, theromatic acridinium ester, imidazole, acridinium salt and oxalate ester. Likewise, a bioluminescent compound may be used to label the antibody of the present invention. Bioluminescence is a type of chemiluminescence found in biological systems in which a catalytic protein increases the efficiency of the chemiluminescent reaction. The presence of a bioluminescent protein is determined by detecting the presence of luminescence. Important bioluminescent compounds for purposes of labeling are luciferin, luciferase and aequorin. The antibody molecules of the present invention may be adapted for utilization in an immunometric assay, also known as a "two-site" or "sandwich" assay. In a typical immunometric assay, a quantity of unlabeled antibody (or fragment of antibody) is bound to a solid support and a quantity of detectably labeled soluble antibody is added to permit detection and/or quantitation of the ternary complex formed between solid-phase antibody, antigen, and labeled antibody. Typical, and preferred, immunometric assays include "forward" assays in which the antibody bound to the solid phase is first contacted with the sample being tested to extract the antigen from the sample by formation of a binary solid phase antibody-antigen complex. After a suitable incubation period, the solid support is washed to remove the residue of the fluid sample, including unreacted antigen, if any, and then contacted with the solution containing a labeled second antibody (which functions as a "reporter molecule") . After a second incubation period to permit the labeled antibody to complex with the antigen bound to the solid support through the unlabeled antibody, the solid support is washed a second time to remove the unreacted labeled antibody. In another type of "sandwich" assay, which may also be useful with the antigens of the present invention, the so-called "simultaneous" and "reverse" assays are used. A simultaneous assay involves a single incubation step as the antibody bound to the solid support and labeled antibody are both added to the sample being tested at the same time. After the incubation is completed, the solid support is washed to remove the residue of fluid sample and uncomplexed labeled antibody. The presence of labeled antibody associated with the solid support is then determined as it would be in a conventional "forward" sandwich assay. In the "reverse" assay, stepwise addition first of a solution of labeled antibody to a fluid sample followed by the addition of unlabeled antibody bound to a solid support after a suitable incubation period is utilized. After a second incubation, the solid phase is washed in conventional fashion to free it of the residue of the sample being tested and the solution of unreacted labeled antibody. The determination of labeled antibody associated with a solid support is then determined as in the "simultaneous" and "forward" assays. Monoclonal antibodies that bind RPTPσ may be radioactively labeled, allowing one to follow their location and distribution in the body after injection. Radioactivity tagged antibodies may be used as a non- invasive diagnostic tool for imaging de novo cells expressing RPTPσ protein, allowing, therefore, for the visualization of the presence of disorders such as neuroblastomas, in which there is an abnormal level of net kinase activity. Immunotoxins may also be designed which target cytotoxic agents to specific sites in the body. For example, high affinity RPTPσ specific monoclonal antibodies may be covalently complexed to bacterial or plant toxins, such as diphtheria toxin, abrin or ricin. A general method of preparation of antibody/hybrid molecules may involve use of thiol- crosslinking reagents such as SPDP, which attack the primary amino groups on the antibody and by disulfide exchange, attach the toxin to the antibody. The hybrid antibodies may be used to specifically eliminate RPTPσ expressing cells. For the production of antibodies, various host animals may be immunized by injection with the RPTPσ protein including but not limited to rabbits, mice, rats, etc. Various adjuvants may be used to increase the immunological response, depending on the host species, including but not limited to Freund's (complete and incomplete) , mineral gels such as aluminum hydroxide, surface active substances such as lysolecithin, pluronic polyols, polyanions, peptides, oil emulsions, keyhole limpet hemocyanin, dinitrophenol, and potentially useful human adjuvants such as BCG (bacille Calmette-Guerin) and Corvnebacterium parvum. Monoclonal antibodies to RPTPσ may be prepared by using any technique which provides for the production of antibody molecules by continuous cell lines in culture. These include but are not limited to the hybridoma technique originally described by Kohler and Milstein, (Nature, 1975, 256:495-497), the human B-cell hybridoma technique (Kosbor et al., 1983, Immunology Today, 4:72; Cote et al., 1983, Proc. Natl. Acad. Sci., 80:2026-2030) and the EBV-hybridoma tech¬ nique (Cole et al. , 1985, Monoclonal Antibodies and Cancer Therapy, Alan R. Liss, Inc., pp. 77-96). in addition, techniques developed for the production of "chimeric antibodies" (Morrison et al., 1984, Proc. 5 Natl. Acad. Sci., 81:6851-6855; Neuberger et al., 1984, Nature, 312:604-608; Takeda et al., 1985, Nature, 314:452-454) by splicing the genes from a mouse antibody molecule of appropriate antigen specificity together with genes from a human antibody 0 molecule of appropriate biological activity can be used. Alternatively, techniques described for the production of single chain antibodies (U.S. Patent 4,946,778) can be adapted to produce RPTPσ-specific single chain antibodies. 5 Antibody fragments which contain specific binding sites of RPTPσ may be generated by known techniques. For example, such fragments include but are not limited to: the F(ab') 2 fragments which can be produced by pepsin digestion of the antibody molecule and the o Fab fragments which can be generated by reducing the disulfide bridges of the F(ab') 2 fragments. Alterna¬ tively, Fab expression libraries may be constructed (Huse et al., 1989, Science, 246:1275-1281) to allow rapid and easy identification of monoclonal Fab 5 fragments with the desired specificity to RPTPσ. 5.5. USES OF RPTPσ CODING SEQUENCE The RPTPσ coding sequence may be used for diagnostic purposes for detection of RPTPσ expression. 0 Included in the scope of the invention are oligoribonucleotide sequences, that include antisense RNA and DNA molecules and ribozymes that function to inhibit translation of RPTPσ. In addition, mutated forms of RPTPσ, having a dominant negative effect, may 5 be expressed in targeted cell populations to inhibit the activity of endogenously expressed wild-type RPTPσ. Such mutated forms of RPTPσ may include, for example, molecules that compete for RPTPσ ligands, thus inhibiting an RPTPσ-induced signal transduction event from occurring. 5.6 USE OF RPTPσ CODING SEQUENCE IN DIAGNOSTICS AND THERAPEUTICS . The RPTPσ DNA may have a number of uses for the diagnosis of diseases resulting from aberrant expression of RPTPσ. For example, the RPTPσ DNA sequence may be used in hybridization assays of biopsies or autopsies to diagnose abnormalities, such as the presence of neuroblastomas, of RPTPσ expression; e.g.. Southern or Northern analysis, including in situ hybridization assays. The RPTPσ cDNA may be used as a probe to detect the expression of the RPTPσ mRNA. In a specific example described herein, in the Working Example presented below in Section 7, the expression of RPTPσ mRNA in rat tissues was analyzed. Briefly, rat RPTPσ is highly expressed in the brain as a 5.7 kb transcript. Rat RPTPσ is also expressed in the lung and intestine as a 6.9 kb transcript but at significantly lower level. Further, RPTPσ is expressed in anatomically distinct regions of rat brain and its expression is developmentally regulated. In εitu hybridization studies confirm that RPTPσ is localized predominantly in the nervous system and can be detected in the rat as early as embryonic day 12 (E12) . During embryonic development, RPTPσ is expressed extensively in the central and peripheral nervous systems, including the trigeminal and dorsal root ganglia as well as retina. In adult rat brain, expression is restricted primarily to the olfactory tubercle, cerebellum, and hippocampus. Within the latter structure, RPTPσ is present in the pyramidal cell layer and the granular layer of dentate gyrus. Also within the scope of the invention are oligo- ribonucleotide sequences, that include anti-sense RNA and DNA molecules and ribozymes that function to inhibit the translation of RPTPσ mRNA. Anti-sense RNA and DNA molecules act to directly block the translation of mRNA by binding to targeted mRNA and preventing protein translation. In regard to antisense DNA, oligodeoxyribonucleotides derived from the translation initiation site, e.g.. between -10 and +10 regions of the RPTPσ nucleotide sequence, are preferred. Ribozymes are enzymatic RNA molecules capable of catalyzing the specific cleavage of RNA. The mecha¬ nism of ribozyme action involves sequence specific hybridization of the ribozyme molecule to complemen¬ tary target RNA, followed by a endonucleolytic cleav- age. Within the scope of the invention are engineered hammerhead motif ribozyme molecules that specifically and efficiently catalyze endonucleolytic cleavage of RPTPσ RNA sequences. Specific ribozyme cleavage sites within any potential RNA target are initially identified by scanning the target molecule for ribozyme cleavage sites which include the following sequences, GUA, GUU and GUC. Once identified, short RNA sequences of between 15 and 20 ribonucleotides corresponding to the region of the target gene containing the cleavage site may be evaluated for predicted structural features such as secondary structure that may render the oligo- nucleotide sequence unsuitable. The suitability of candidate targets may also be evaluated by testing their accessibility to hybridization with complemen- tary oligonucleotides, using ribonuclease protection assays. Both anti-sense RNA and DNA molecules and ribozymes of the invention may be prepared by any method known in the art for the synthesis of RNA molecules. These include techniques for chemically synthesizing oligodeoxyribonucleotides well known in the art such as for example solid phase phosphoramidite chemical synthesis. Alternatively, RNA molecules may be generated by in vitro and in vivo transcription of DNA sequences encoding the antisense RNA molecule. Such DNA sequences may be incorporated into a wide variety of vectors which incorporate suitable RNA polymerase promoters such as the T7 or SP6 polymerase promoters. Alternatively, antisense cDNA constructs that synthesize antisense RNA cons itutively or inducibly, depending on the promoter used, can be introduced stably into cell lines. Various modifications to the DNA molecules may be introduced as a means of increasing intracellular stability and half-life. Possible modifications include but are not limited to the addition of flanking sequences of ribo- or deoxy- nucleotides to the 5' and/or 3' ends of the molecule or the use of phosphorothioate or 2' O-methyl rather than phospho- diesterase linkages within the oligodeoxyribonucleo- tide backbone. 5- USE OF RPTPσ OR LIGANDS Depending on the individual molecule and the cellular environment in which the molecule is found, some RPTPσ molecules may become activated upon extracellular ligand binding, and others may become inactivated (the activity referred to here being RPTPσ phosphatase activity) . Ligand binding to RPTPσ molecules may affect a variety of cellular processes. Such processes may include, but are not limited to, normal cellular functions such as differentiation, metabolism, and cell cycle control; cellular behavior, such as motility and contact inhibition; in addition to abnormal or potentially deleterious processes such as virus-receptor interactions, inflammation, and cellular transformation to a cancerous state. As demonstrated in the Working Example presented., below, in Section 7, RPTPσ mRNA is predominantly expressed in neuronal tissue. This neuronal expression is developmentally regulated, with the first RPTPσ mRNA transcripts being detectable during embryogenesis. In addition, the neuronal expression of RPTPσ is spatially restricted, with transcripts being expressed in specific regions of neuronal tissue. Thus, cellular processes, such as those described above, may be involved in the regulation of neuronal development, differentiation, and metabolism. The methods described below, therefore, may be useful in the identification of compounds capable of treating RPTPσ-related neuronal disorders, such as, potentially, neuroblastomas. RPTPσ, its equivalent derivatives, and analogs, and ligands of such molecules may be used as drugs that can modulate the cellular processes under the control of RPTPσ. In addition, methods are presented below for the identification of compounds that affect RPTPσ activity, and such compounds may also be used as drugs that can modulate' one or more of the cellular processes mentioned above. RPTPσ or RPTPσ derivatives or analogs, or ligands of such molecules may be used directly to modulate processes such as those mentioned above. For example, soluble RPTPσ may be produced and administered, using techniques well known to those skilled in the art, that would be capable of competing with endogenous transmembrane RPTPσ molecules for available ligands, thus reducing or inhibiting ligand binding to endogenous RPTPσ. Such soluble RPTPσ molecules may consist of all or part of the extracellular domain of the RPTPσ molecule, i.e.. may contain all or part of from about amino acid 24 to about amino acid 850 (before signal sequence cleavage) of the RPTPσ protein. The effect of such a procedure would be to activate, reduce or block (depending on what the usual effect of ligand binding to the particular native RPTPσ molecule in question is) the biological activity of the native RPTPσ molecule. The RPTPσ molecules used here may include the entire molecule or, alternatively, only the RPTPσ extracellular domain, or a part of the RPTPσ extracellular domain thereof. In addition, RPTPσ ligands may be administered, again, using techniques well known to those in the art. (Methods for the identification of such ligands are presented below.) Such administration would lead to a greater than normal number of transmembrane RPTPσ being bound by ligand, potentially causing an amplification of the ligand-bound state within cells exhibiting RPTPσ. Alternatively, the administered ligand may be composed of a modified form of said ligand such that receptor binding may still occur, but the normal result of such binding (receptor activation or inactivation, as the case may be) does not occur. A ligand with such a design would act in much the same way that administration of soluble RPTPσ would, in that both procedures would have the final effect of reducing the number of functionally bound RPTPσ transmembrane molecules, therefore lowering or blocking the. normal extracellular signal being transduced into the RPTPσ-exhibiting cell via normal ligand binding to transmembrane RPTPσ. Depending on the specific conditions being treated, agents may be formulated and administered systemically or locally. Techniques for formulation and administration may be found in "Remington's Pharmaceutical Sciences," 18th Edition, Mack Publishing Co., Easton, PA, 1990. Suitable routes may include oral, rectal, transmucosal, or intestinal administration; parenteral delivery, including intramuscular, subcutaneous, intramedullary injections, as well as ,intrathecal, direct intraventricular, intravenous, intraperitoneal, intranasal, or intraocular injections, just to name a few. For injection, the agents of the invention may be formulated in aqueous solutions, preferably in physiologically compatible buffers such as Hanks's solution, Ringer's solution, or physiological saline buffer. For such transmucosal administration, penetrants appropriate to the barrier to be permeated are used in the formulation. Such penetrants are generally known in the art. RPTPσ may also be used to screen for additional molecules that can act to modulate the activity of cellular processes such as those described above. For example, compounds that bind to RPTPσ may be identified. Such molecules may include, but are not limited to, natural ligands of RPTPσ, other proteins or glycoproteins, or small synthetic molecules. One method • that may be pursued in the isolation of such RPTPσ-binding molecules would include the attachment of RPTPσ molecules to a solid matrix, such as agarose or plastic beads, microtiter wells, or petri dishes, and the .subsequent incubation of attached RPTPσ molecules in the presence of a potential RPTPσ-binding compound or compounds. After incubation, unbound compounds are washed away, and the RPTP-bound compounds are recovered. In this procedure, large numbers of types of molecules may be simultaneously screened for RPTPσ-binding activity. Bound molecules could be eluted from the RPTPσ molecules by, for example, competing them away from the RPTPσ molecules with the addition of excess ligand, or by changing the pH and/or ionic environment of the bound molecules. The effect of a compound on the phosphatase activity of RPTPσ molecules can also be determined. Such a compound may, for example, be one isolated using a procedure such as the binding technique described above. One method that may be utilized for determining the effects of a compound on RPTPσ phosphatase activity may involve exposing such a compound to a preparation of cultured cells that express the RPTPσ of the invention, and subsequently measuring the phosphatase activity of the culture. The compound of interest may be introduced to the cells, for example, by addition of the compound to the tissue culture medium. The phosphatase activity of the cells within the tissue culture preparation may be determined by measuring the level of cellular phospho¬ tyrosine within the culture, using method that are well known in the art (Honegger et al.. 1987, Cell 51:199-209; Margolis et al.. 1989, Cell 57:1101-1107) . To properly determine the effects of addition of the compound, the cellular phosphotyrosine levels of the same type of tissue culture preparation that has not been exposed to this compound must also be measured, and the two levels must then be compared. For example, RPTPσ molecules may be incorporated into apparatuses including but not limited to affinity columns such that large numbers of molecules may be screened quickly by being applied to said apparatuses. Those molecules with an affinity for RPTPσ will be bound. Such binding will also bring about a partial purification of the molecules of interest. In order to continue the purification process, the bound molecules should be eluted off the above described apparatuses, for example by competing them away from the RPTPσ with excess ligand, and the process would then be repeated until the molecule of interest is purified to the extent necessary. Having now generally described the invention, the same will be more readily understood through reference to the following example which is provided by way of illustration, and is not intended to be limiting of the present invention, unless specified. EXAMPLE: ISOLATION AND ANALYSIS OF RAT RPTPσ cDNA CLONES 6.1. Isolation Of Novel PTPase Domains From Total RNA OF PC12 Cells Bv PCR A pair of degenerate oligomers: 5'-GA(T/C)TA(T/C)AT(T/C)AA(T/C)GCI AG(T/C)TT-3' (SEQ ID NO:8) and 5'A(T/C)ICCIGC(A/G)CT(A/G)CA(A/G)TGIAC-3 » (SEQ ID NO:10), corresponding to conserved amino acid stretches DYINAS (SEQ ID NO:9) and VHCSAG (SEQ ID NO:11) of known PTPase domains, was used in the RNAPCR to specifically amplify novel sequences of PTPase domain from 1 μg of PC12 total RNA (following procedures recommended by Perkin Elmer/Cetus) . PCR products of expected size (about 450 bp) were isolated by agarose gel electrophoresis, purified and then cloned into a pBluescript vector (Stratagene) . The cDNA inserts were sequenced.by the dideoxy chain termination method using the Sequenase Version 2.0 Kit. Sequencing of about 100 individual clones led to the identification of three PTPase domains whose predicted sequences were homologous to, but distinct from, corresponding sequences of all known PTPs. 6.2. Library Screening And Isolation Of cDNA Clones The cDNA insert from one of the above PTPase domains, referred to as the σ PTPase domain, was amplified and labelled using a random priming labelling kit. The labelled cDNA insert was then used as a probe to screen a rat brain stem cDNA library (Sambrook, J. et al . , MOLECULAR CLONING: A LABORATORY MANUAL , 2nd Edition, Cold Spring Harbor Press, Cold Spring Harbor, NY (1989)). About 600,000 recombinants were screened, from which seventeen positive clones were purified after the first round of screening. The most 5' end of the longest cDNA insert isolated following the first round °f screening was used in successive rounds of screening until overlapping cDNA clones that contained the entire coding sequence for RPTPσ were obtained. Both strands of several overlapping cDNA clones were sequenced using a Pharmacia DNA Sequencer. 6.3. Sequence Alignments All DNA and protein database searches were done with the Genetic Computer Group sequence analysis software package (Devereux et al . , Nucleic Acid Res . 12:387-396 (1989)). The SwissProt and Gene Bank\European Molecular Biology Laboratory databases were searched with FASTA and TFASTA programs, respectively (Pearson and Lipman, Proc . Natl . Acad . Sci . 85:2444-2448 (1988)). Protein sequences were aligned with the Genetics Computer Group programs, LINEUP, PILEUP, PRETTY and BESTFIT. 6.4. Results and Discussion 6.4.1. Molecular Cloning of the full-length cDNA for RPTPσ Three cDNA fragments coding for novel PTPase domains were initially identified in the total RNA isolated from PC12 cells by reverse PCR with the primers for the conserved regions of other known PTPs. One of these PTPase domains, termed the σ PTPase domain, was expressed at high levels in the brain and only to a limited extent in the lung and intestine. Based on these observations, a random and oligo-dT primed rat brain stem cDNA library (Clontech Inc.) was screened for the full length cDNA of RPTPσ using the PCR fragment initially cloned from the RNA of PC12 cells. After three rounds of screening, several overlapping clones were isolated. They were sequenced in both directions. As shown in FIG. l, the 5.7 kb full length cDNA for RPTPσ was constructed by joining the two longest overlapping clones (H-29 and B-10) at a unique Mlul site. The 5.7 kb cDNA has an open reading frame of 1501 amino acid residues starting from the ATG at bp 833. The ATG was preceded by stop codons in all three reading frames and meets the requirements for the translation initiation site (Kozak, M. (1984) Nucl. - Acid -Res. 12:857-871). There is an 832 bp 5•- untranslated sequence and a 352 bp 3 '-untranslated sequence containing a polyA tail. 6.4.2. Characterization of RPTPσ The deduced amino acid sequence for RPTPσ is shown in FIG. 2(A)-2(G) . It contains 23 hydrophobic amino acid residues that may function as a signal peptide (von Heijne, G. (1986) Nucl . Acid Reε . 14:4683-4691), followed by an 824 amino acid extracellular domain and a 24 hydrophobic amino acids transmembrane domain. The 627 amino acid cytoplasmic region contains two tandem PTPase domains. The overall sequence of RPTPσ demonstrates a high degree of similarity to rat LAR (Yu et al . , supra) , having 71 % sequence identity within the entire coding region. RPTPσ is also 75% identical to partially sequenced hPTP-5 (Krueger et al . , supra) . The extracellular segment of RPTPσ consists of 3 Ig-like domains (residue 33 to 315); Williams, A.F. (1987) Immunol. Today 8:298-303) and 5 FNIII-like repeats (residue 320 to 786; Kornblihtt, A.R. et al., (1985) EMBO J . 4:1755-1759; Hynes, R. (1985) Ann . Rev . Cell Biol.1:67-90) . Search in database revealed significant homology to the extracellular segments of rat LAR (63% identity) . Also, the homology between the Ig-like domains of RPTPσ and LAR (75% identity) is greater than that of the FNIII-like repeats (54% identity) . There was significant homology also between the FNIII-like repeats of RPTPσ and hPTP-5. In addition, the extracellular sequence of RPTPσ is homologous to neural cell adhesion molecules in overall structure and sequence. The highest homology was detected with LI (26% identity) (Moos, M. et al . , (1988) Nature 334 : 701-703 ) , followed by N-CAM (22% identity) (Barthers et al . ) and neuroglian (22%) (Bieber, A.J. et al . , (1989) Cell 59:447-460) . FIG. 3 shows alignment of three Ig domains of RPTPσ to each other and to the first Ig domain of rat LAR and mouse N-CAM/ respectively. Within each Ig domain, two cysteines are thought to be involved in intradomain disulfide binding, are conserved (FIG. 3, asterisks). The alignment of the five FNIII-like repeats of RPTPσ to each other and to the first FNIII-like repeat of rat LAR and type III repeat (domain 7) of human fibronectin is shown in FIG. 4. The fifth repeat of RPTPσ exhibits greater divergence from consensus than other four. Also, the extracellular region of RPTPσ does not contain the RGD sequence that is required for fibronectin binding (Ruoslahti, E. et al . (1986) Cell 44:517-518) . The cytoplasmic segment of RPTPσ, like most receptor tyrosine phosphatases, contains two conserved PTPase domains in tandem. PTPase domain I shows 47% sequence identity with PTPase domain II (FIG. 5) . The cysteine residues, which have been implicated to be essential for phosphatase activity, are conserved in both PTPase domains. The overall cytoplasmic segment of RPTPσ has a striking sequence homology to that of rat LAR (84% identity) and hPTP-5 (86% identity) . Furthermore, comparison of the cytoplasmic segments of RPTPσ and rat LAR indicates that a higher degree of identity is present between domain II (93%) than domain I (84%) . A schematic diagram showing the multiple domain structure of RPTPσ is presented in FIG. 5. Although RPTPσ is highly homologous to rat LAR, especially in the cytoplasmic region, the diversity of their extracellular domains, particularly in the FN Ill-type repeats, demonstrates that RPTPσ is a new member of the type II receptor tyrosine phosphatases. The nucleotide sequence of RPTPσ (SEQ ID NO:l) is shown in FIG. 2(A)-2(G). The complete amino acid sequences of RPTPσ (SEQ ID NO:2) is also shown in FIG. 2 (A)-2(G). A database search revealed that RPTPσ is structurally similar to rat LAR with an overall sequence identity of 71%. Homology among the cytoplasmic domains (84%) is greater than that of the extracellular domains (63%) . RPTPσ was mapped to distal chromosome 17 of the mouse, which corresponds in part to human chromosome 6 and 19. Hence, we conclude that RPTPσ is a novel member of the type II receptor tyrosine phosphatases. Unlike rat LAR which has 6 predicted N- glycosylation sites, no such sites have been found in the extracellular domain of RPTPσ. However, this domain is rich in serine and threonine residues (16%) and likely to provide multiple attachment sites for O- linked glycosylation. Moreover, RPTPσ has only five FNIII repeats while LAR contains eight. It is possible that larger alternatively spliced transcript (6.9 kb) encodes a protein containing eight FNIII-like repeats. Like other type II receptor tyrosine phosphatases, such as PTP-μ, RPTPK, DLAR and DPTP, the extracellular segment of RPTPσ consists of both Ig- like and FNIII-like repeats. This structural feature also has been identified in neural cell adhesion molecules such as N-CAM, NG-CAM and NR-CAM (Edelman et al → . , εupra ; Grumet et al . , εupra) . It has been demonstrated that the extracellular domain, especially the Ig-like repeats of these neural adhesion molecules, is crucial for mediating homophilic and heterophilic binding when expressed in transfected cells (Edelman, G.M. et al . (1987) Proc . Natl . Acad . Sci . USA 84:8502-8505; Mauro, V.P. et al . , (1992) J . Cell Biol . 119:191-202). Since there is significant homology among the extracellular domains of RPTPσ and LI, N-CAM and neuroglian (26%, 22% and 22% identity, respectively) , it is possible that the extracellular domain of RPTPσ also mediate such binding which, in turn, couples the tyrosine phosphatase activity to some intracellular signalling pathway. Immunoblot analyses suggest that RPTPσ, like LAR and RPTP , undergoes proteolytic processing. Sequence analysis indicate that RPTPσ has several potential cleavage motifs, such as RK at residues 731-732, RR at 762-763, and RHSR at residues 766-769; all located within the 5th FNIII repeat of the extracellular domain. These sites may serve as specific cleavage signals for proteolytic processing (Barr, P.J. (1991) Cell 68:1-3) . 7. EXAMPLE: EXPRESSION AND TISSUE DISTRIBUTION OF RPTPσ 7.1. Methods 7.1.1. RNA Isolation And Northern Blot Analysis Total RNA was isolated from different tissues of 6 day old rats using RNA isolation kits obtained from Stratagene. Samples containing 20 μg of total RNA were resolved in a formaldehyde/agarose gel (Sambrook et al . , supra) and then transferred to Nytran membrane (Schleicher & Schuell) . Probes corresponding to different cDNA regions of RPTPσ were amplified by PCR, purified, and labelled using a random priming kit. Hybridization and subsequent washing were carried out essentially as described (Ausubel, F.M. et al . , Current Protocols in Molecular Biology, Wiley Interscience, NY, 1989 ) with an additional wash carried out in 0.1 x SSC and 0.1% SDS at 60°C for 15 min. 7.1.2. JN SITU Hybridization Probe-l had the following nucleotide sequence (5'to 3') : TAGACCACAATGGAACCATCGTTGTCAGGCTTTGGGGCGACACTAGGCTT (SEQ ID NO:12). Probe-l was synthesized in an Applied Biosystems 380A DNA Synthesizer and then purified. Probe-l is antisense and complementary to the cDNA of RPTPσ from nucleotide 2918 to 2967; a region that encodes amino acid stretch KPSVAPKPDNDGSIWY (SEQ ID NO:3) from residue 694 to 710. This probe was chosen because it is least homologous to the corresponding sequences in rLAR and hPTP-<5. Probe-l was labelled at 3'-end with [α- 35 S]dATP using a terminal deoxynucleotidyl transferase kit and was then purified by Sephadex G-25 column chromatography. The specific activities of the labelled probe ranged from 1 to 4 x 10 8 cpm/μg DNA. Adult male and timed-pregnant female Sprague- Dawley rats and their litters were used for the study. The day of successful copulation was determined by the presence of sperm in vaginal smears and recorded as embryonic day 0 (E0) . The day of birth was considered postnatal day 0 (PO) . Whole bodies of E12 embryos were fixed in 4% paraformaldehyde in 0.1 M sodium phosphate, pH 7.4, for 4 hours followed by overnight infiltration with 15% sucrose in 0.1 M sodium phosphate, pH 7.4. Adult rats were sacrificed by decapitation and then the brains were rapidly removed and frozen on dry ice. 20 μm sections obtained with a cryostat microtome were postfixed for 30 min, and then washed three times in 0.1 M sodium phosphate, pH 7.4. The sections were then dehydrated and stored at -20°C. Prehybridization and hybridization were carried out as described elsewhere (Barnea et al. , εupra ; Levy, J.B. et al . , (1993) J. Biol. Chem. in press). Sections were mounted on the slides and incubated with 1 x 10 6 CPM labelled probe-l in 10 mM DTT. The specificity of hybridization was determined by incubating an adjacent section with labelled probe-l in the presence of a 70 fold excess of unlabelled probe-l. The slides were washed twice in 2 x SSC at room temperature (30 min) , 1 x SSC at 50°C (30 min) , 0.5 x SSC at 50°C (30 min) and finally in 0.5 x SSC at room temperature (10 min) . Sections were dehydrated and exposed to X-Omat film for 10 days. 7.1.3. Generation Of Antibodies Against RPTPσ-GST Fusion Proteins And Peptide Derived From RPTPσ The cDNA fragments coding for amino acid 100 to 510, 512 to 835 and 964 to 1501, respectively, were amplified by PCR and subcloned into a pGEX expression vector (Pharmacia) to construct corresponding recombinant plasmids (pGEX-EX,PGEX-FNIII, pGEX-CY respectively) . After induction with IPTG, the insoluble GST fusion proteins produced from each of the above constructs were isolated by SDS-PAGE. Two rabbits were immunized with the fusion protein to produce polyclonal antisera against RPTPσ. The polyclonal antibodies against amino acid 512 to 835 was designated as FNIII antibodies. Three peptides, HAI-1,2 and 3, corresponding amino acid 795 to 809, 1488 to 1501 and 27 to 41 of RPTP-σ, respectively, were synthesized chemically and conjugated with carrier protein, KLH. Two rabbits were immunized with each fusion protein conjugate to produce polyclonal antisera against the peptides of RPTP-σ. 7.1.4. Transfection, Immunoprecipitation And Immunoblot Analyses A cDNA insert containing the entire open reading frame of RPTPσ was subcloned into an eukaryotic expression vector to generate RKSigma and RKSigmaR, in which the cDNA insert was oriented in the sense or antisense direction, respectively. Human embryonic kidney 293 cells, grown to 20% confluence on fibronectin coated dishes, were transiently transfected with appropriate plasmids by the calcium phosphate precipitation method (Ausubel et al . , supra) . The transfected cells were harvested after 48 hrs and lysed in RIPA buffer (137 mM NaCl, 10% glycerol, 1% Triton X-100, 0.5% deoxycholate, 0.1% SDS, 2 mM EDTA, 20 mM Tris, pH 7.3) containing proteinase inhibitors aprotinin and leupeptin (l μg/ml) and PMSF (100 μg/ml)]. After centrifugation (15,000g, 15 min at 4°C), the supernatants were analyzed by either (1) immunoprecipitation with FNIII Ab followed by immunoblot analysis or (2) directly by immunoblot analysis. The proteins resolved by SDS- PAGE were transferred onto Nytran membranes, immunoprobed with FNIII Ab, and visualized with 15 I- Protein-A after exposure to X-ray film. 7.2. Results And Discussion 7.2.1. Distribution Of RPTPσ mRNA Northern blot analyses of total RNA isolated from various rat tissues (6 days old) are presented in FIG. 6. The blot depicted in this figure was probed with a cDNA fragment coding for amino acid residues 408 to 521 of RPTPσ. Identical results were obtained with cDNA probe specific for a cytoplasmic segment of RPTPσ. There are three RPTPσ transcripts of 5.7, 6.9 and 8.5 kb. The 5.7 kb transcript, the most abundant species, and the 8.5 kb transcript were expressed exclusively in brain. The 6.9 kb transcript was expressed to a significantly lesser extent in brain 5 and also in lung and intestine. The cDNA that was sequenced and described herein probably corresponded to the 5.7 kb mRNA. 7.2.2. JN SITU Hybridization 0 Since RPTPσ is highly expressed in the brain as detected by Northern blot analysis, its expression at specific sites within whole embryos and adult rat brain was then identified by in εitu hybridization. Using labelled probe-l, an antisense oligomer, the 5 expression of RPTPσ was detected in brain, spinal cord, and dorsal root ganglia as early as embryonic day E12 (FIG. 7(A)). No apparent expression was detected in other tissues. Hybridization signals were specific since they were completely chased by a 70- o fold excess of unlabelled probe-l (FIG. 7(B)). In addition, a relatively low level of the expression of RPTPσ was detected in the lung at embryonic day 18 (E18) and the intensity of RPTPσ expression overall gradually decreased during embryonic development. 5 In the adult rat brain, expression of RPTPσ was confined to specific regions of the brain that included the olfactory bulb, cerebellum and hippocampus (FIG. 7(C)). Within the latter structure, the pyramidal cell layer and granular layer of dentate 0 gyrus were labelled specifically (Figures 7(C), 7(D)). 7.2.3. Transient Expression Of RPTPσ Human embryonic kidney 293 cells were transfected transiently with a mammalian expression vector that 5 directs the synthesis of RPTPσ in order to investigate its biochemical properties. The transfected cells were lysed in REPA buffer and the supernatants then subjected to immunoprecipitation with polyclonal FNIII Ab. This was followed by immunoblot analysis using the same antibodies. The results shown in FIG. 8, panel A, revealed that FNIII Ab can specifically detect a protein of 200 kDa in supernatants from cells transfected with a plasmid containing RPTPσ cDNA (RKSigma) (FIG. 8, panel A, lane 1) but not from those transfected with a plasmid containing control DNA (RKSigmaR) (FIG. 8 panel A, lane 2) . No band corresponding to the 200 kDa protein was detected in control immunoprecipitation experiments using preimmune serum. The apparent molecular weight of the expressed protein after SDS-PAGE is in good agreement with the expected size for RPTPσ. The bands detected in lane 2 of FIG. 8, panels A and B, were non-specific since they were also observed after incubation with preimmune serum. Several members of the type II tyrosine phosphatases, such as LAR (Streuli, M. et al. , (1992) EMBO J . 11:879-907) and PTP-J (Jiang et al . , supra) , undergo proteolytic processing after synthesis. To investigate whether similar processing occurs with RPTPσ, the supernatants of lysates from the transfected cells were subjected directly to immunoblot analysis using FNIII Ab or preimmune serum. The results presented in FIG. 8, panel B show that in addition to the 200 kDa protein previously identified, an additional protein with an apparent molecular weight of 100 kDa was detected in lysates of cells transfected with plasmid RKSigma (lane 1) , but not with RKSigmaR (lane 2) . No such bands at 200 and 100 kDa were detected with preimmune serum. Identical results also were obtained in immunoblot experiments with the supernatants from lysates of transfected COS-1 cells. These results suggest that RPTPσ also undergoes proteolytic processing and the 100 kD protein may represent a cleavage product. Numerous studies have indicated that CD45 plays a crucial role in coupling the T cell antigen receptor to a intracellular signaling pathway (Trowbridge, I.S. (1991) J . Biol . Chem . 266:23517-23520; Shaw, A. et al. (1991) Curr. Opin . Cell Biol . 3:862-868; Desai, D.V. et al . , (1993) Cell 73:1-20). Experiments have suggested CD45 can activate Lck or fyn protein tyrosine kinases by dephosphoryIation at inhibiting sites at the carboxy-terminus (Shiroo, M. et al . , (1992) EMBO J . (1992) 11:4887-4897; Mustelin, T. et al . , (1989) Proc . Natl . Acad . Sci . USA 86:6302-6306) . In the mammalian nervous system several tyrosine kinases such as c-yeε (Sudol, M. et al . , (1889) Mol . Cell . Biol . 9:4545-4549), and the neuron-specific form of c-src (Ross, CA. et al . , (1988) Proc . Natl . Acad . Sci . USA 85:9831-9835) have been shown to be expressed at high levels in the brain. Moreover, protein tyrosine kinase inhibitors have been shown to block long-term potentiation in the hippocampus (O'Dell, T.J. et al . , (1991) Nature 353:558-560). Furthermore, it has been demonstrated that several receptor tyrosine kinases, such as NGF and FGF receptors (Chao, M.V. (1992) Neuron 9:583-593), play a central role in neural development. The molecular cloning of RPTPσ, which is expressed primarily in both the central and peripheral nervous systems of embryo and adults, will assist in the determination of the role of tyrosine phosphatases in mammalian neurogenesis and maintenance. 8. EXAMPLE: CHROMOSOMAL LOCALIZATION OF THE MURINE RPTPσ GENE Inbred and recombinant inbred (RI) mice were obtained from The Jackson Laboratory (Bar Harbor, ME) . Genomic DNA was isolated from liver, digested with restriction enzyme TaqI, and then analyzed by Southern blotting with probe PGEX-FNIII (see above) as described previously (D'Eustachio, P. et al . , (1987) Immunogenetics 26:339-343). To establish genetic linkages, the distribution patterns observed for RPTPσ in the RI strains were compared to approximately 1360 other markers maintained in a database at New York University by Dr. P. D'Eustachio. Significance of matches was assessed using the BAYLOC algorithm (Blank, R.D. et al . , (1988) Genetics 120:1073-1083). When Taql-digested genomic DNA from various inbred strains was analyzed by Southern blotting using an RPTPσ probe (pGEX-FNIII) , two allelic forms of the gene were detected (Table IA) . The pattern of inheritance of these alleles in recombinant inbred strains of mice defined a single genetic locus (Table IB) . Comparison of the inheritance pattern for this locus with these previously established for approximately 1360 markers distributed over the entire mouse genome allowed us to map the locus for RPTPσ to distal mouse Chromosome 17. TABLE I DNA FRAGMENT LENGTH VARIANT ASSOCIATED WITH THE HOUSE RPTP/e GENE A.Alleles of RPTPσ defined bv Southern Blotting Allele (Size kb) ) Strains a 5.6AKR, 020/A, DBA/2J, C57BL/6J, C3H/HeJ, BALB/C, NZB/B1NJ, SM/J, A/J, PL/J J 5.4C57L/J, SWR/J, SJL/J, STS/A, 129/J B.Inheritance of RPTPσ Alleles in Recombinant Inbred strains AKXLBXJNX129 111111 12222 233 11 56789 234567 91458 97812106 LAAAA LAALL AALLL LLL JBN9N CXSCXJ 1 1111 1 12345 67890 123413468 95 CSSSS SCCCC CSCSCCJJC CC C. Linkage Relationships Deduced from RI Typing Data Marker Chr R/N OddsDistance in cM (95% limits) H-2178/390.03248 7.4 (2.7-20.1) C3170/140.00634 — (<8.9) i?asI2-3170/ 180.00049 — (<6.4) Hprt-2 pεl71/180.00972 1.5 (0.0-11.6) (A)Variant DNA fragments in Southern blots of Taql-digested genomic DNA. (B)A11 RI strains were homozygous for one of the progenitor strain alleles of RPTPσ, as indicated by the generic symbols: 9, 129/J-like; A, AKR/J-like; B, C57BL/6J-like; C, BALB/c-like; J, SJL-like; , C57 /J-Iike; N, NZB/BINJ-Iike; and S, STS/A-like. (C)The strain distribution pattern for RPTPσ was compared to ones for 436 other markers. All concordances whose odds of chance occurrence are less than 0.05 are shown. For each such match, the Marker name and chromosomal location (Chr) are shown, together with the observed recombination fraction (R/N) , Odds of observing that fraction or a smaller one by chance (Blank, R.D. et al., (1988) Genetics 120:1073-1083)-, and, conditional on the existence of linkage, the estimated distance in cM between the two loci and the 95% binomial confidence limits for that estimate. The references cited above are all incorporated by reference herein, whether specifically incorporated or not. Having now fully described this invention, it will be appreciated by those skilled in the art that the same can be performed within a wide range of equivalent parameters, concentrations, and conditions without departing from the spirit and scope of the invention and without undue experimentation. While this invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modifications. This application is intended to cover any variations, uses, or adaptations of the inventions following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth as follows in the scope of the appended claims. SEQUENCE LISTING (1) GENERAL INFORMATION: (i) APPLICANT: Schleββinger, Joseph Yan, Hal (ii) TITLE OF INVENTION: NOVEL RECEPTOR-TYPE PROTEIN PHOSPHOTYROSINE PHOSPHATASE-SIGMA (iii) NUMBER OF SEQUENCES: 12 (iv) CORRESPONDENCE ADDRESS: (A) ADDRESSEE: Pennie £ Edmonds (B) STREET: 1155 Avenue of the Americas (C) CITY: New York (D) STATE: New York (E) COUNTRY: U.S.A. (F) ZIP: 10036-2711 (V) COMPUTER READABLE FORM: (A) MEDIUM TYPE: Floppy disk (B) COMPUTER: IBM PC compatible (C) OPERATING SYSTEM: PC-DOS/MS-DOS (D) SOFTWARE: Patentin Release #1.0, Version #1.25 (vi) CURRENT APPLICATION DATA: (A) APPLICATION NUMBER: US (B) FILING DATE: 25-AUG-1993 (C) CLASSIFICATION: ( iii) ATTORNEY/AGENT INFORMATION: (A) NAME: Misrock, S. Leslie (B) REGISTRATION NUMBER: 18,872 (C) REFERENCE/DOCKET NUMBER: 7683-043 (ix) TELECOMMUNICATION INFORMATION: (A) TELEPHONE: 212-790-9090 (B) TELEFAX: 212-869-8864/9741 (C) TELEX: 66141 PENNIE (2) INFORMATION FOR SEQ ID NO:l: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 11 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: unknown (D) TOPOLOGY: unknown (ii) MOLECULE TYPE: peptide . (ix) FEATURE: (A) NAME/KEY: Modified-βite (B) LOCATION: 1 (D) OTHER INFORMATION: /label= Xaa /note= "Xaa = Isoleucine or Valine" (ix) FEATURE: (A) NAME/KEY: Modified-site (B) LOCATION: 4 (D) OTHER INFORMATION: /label= Xaa /note= "Xaa = any amino acid" (ix) FEATURE: (A) NAME/KEY: Modified-βite (B) LOCATION: 7 (D) OTHER INFORMATION: /label= Xaa /note* "Xaa ■ any amino acid" (ix) FEATURE: (A) NAME/KEY: Modified-site (B) LOCATION: 8 (D) OTHER INFORMATION: /label* Xaa /note* "Xaa * any amino acid" (ix) FEATURE: (A) NAME/KEY: Modified-site (B) LOCATION: 10 (D) OTHER INFORMATION: /label* Xaa /note* "Xaa * Serine or Threonine* (xi) SEQUENCE DESCRIPTION: SEQ ID NO:l: Xaa His Cys Xaa Ala Gly Xaa Xaa Arg Xaa Gly 1 5 10 (2) INFORMATION FOR SEQ ID NO:2: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 5690 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: unknown (D) TOPOLOGY: unknown (ii) MOLECULE TYPE: DNA (genomic) (ix) FEATURE: (A) NAME/KEY: CDS (B) LOCATION: 833..5338 (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2: GGCACGAGCC AGACACTAGC TGAAAAGTCA GGTGACAGAA ACAATGATTC AGACTGATCA 60 CATGATTACA AAGCTGGGGG CTCCAGCAGG GCTCCAGGTG GTCGGGGTGG ACATCTAAGG 120 AAGCAGTGAC ATGGGAGGGG CAAGCACTGG GCCAGCCTTG AGCCGCCTGG ATGACAGAGA 180 CAGAGGATCT GGTAGCTCCA GGGATCTCCG GTCCATGCCT TACTTGGCCA GGGGGTTCCT 240 GAAGGACCTG CCGGCAAACT TGGCTTTGCT GCCCAGCTCC TCCTCGATTC TAAGGATCTG 300 ATTGTACTTG GCCAGGCGCT CAGATCGGCA GGGGGCACCA GTCTTGATCT GCCCAGTGCA 360 GAGCCCCACC ACCAGGTCGG CAATGAAAGT GTCCTCAGTC TCCCCAGATC GATGGGACAC 420 CATGACACCC CAGCCATTGG ACTGGGCCAG CTTACACGCC TGCAGAGACT CGGTCACAGA 480 GCCAATCTGG TTCACTTTGA GCAGGAGGCA GTTGCAGGAC TTTTCGCCTG CAGCCTTGGC 540 GATCCGCTTA GGGTTGGTCA CTGTGAGGTC ATCCCCCACC ACCTGGATGC CTGCAGTAGC 600 TGTGAACTTC TGCCAAGCAT CCCAGTCGTC CTGGTCAAAG GGATCTTCAA TGGACACCAC 660 TGGGTAGTCC TTGATGAAGG ACTTGTACAG GTCGGCCAGC TGGTCGGGTG TGATGTACCG 720 GCTGGCATCA TCTGGAGACT TGAAGTCCAG GTCATACTTG CCAGCCCTGT AGAATTCGGA 780 GGCAGCCACA TCCATCCCCC ACCAGGGCGG AGGCTGGAGG CCACTGCCAA GC ATG 835 Met 1 GCG CCC ACC TGG AGA CCC AGC GTG GTG TCT GTG GTG GGT CCT GTG GGG 883 Ala Pro Thr Trp Arg Pro Ser Val Val Ser Val Val Gly Pro Val Gly 5 10 15 CTC TTC CTT GTA CTG CTG GCC AGA GGG TGC TTG GCT GAA GAG CCA CCC 931 Leu Phe Leu Val Leu Leu Ala Arg Gly Cyβ Leu Ala Glu Glu Pro Pro 20 25 30 AGA TTT ATC AGA GAG CCC AAG GAT CAG ATT GGT GTG TCA GGA GGC GTG 979 Arg Phe lie Arg Glu Pro Lys Aβp Gin lie Gly Val Ser Gly Gly Val 35 40 45 GCC TCC TTC GTG TGC CAG GCC ACA GGT GAC CCT AAG CCA CGG GTG ACC 1027 Ala Ser Phe Val Cys Gin Ala Thr Gly Asp Pro Lys Pro Arg Val Thr 50 55 60 65 TGG AAC AAG AAG GGC AAG AAA GTG AAC TCA CAG CGC TTT GAG ACC ATT 1075 Trp Asn Lys Lys Gly Lys Lys Val Asn Ser Gin Arg Phe Glu Thr lie 70 75 80 GAC TTT GAC GAG AGC TCG GGG GCC GTG CTG AGG ATC CAG CCA CTT CGG 1123 Asp Phe Asp Glu Ser Ser Gly Ala Val Leu Arg lie Gin Pro Leu Arg 85 90 95 ACA CCC CGG GAT GAG AAC GTG TAC GAG TGT GTG GCC CAG AAC TCG GTG 1171 Thr Pro Arg Asp Glu Asn Val Tyr Glu Cys Val Ala Gin Asn Ser Val 100 105 110 GGG GAG ATC ACA GTT CAT GCG AAG CTC ACC GTC CTG CGA GAG GAC CAG 1219 Gly Glu lie Thr Val His Ala Lye Leu Thr Val Leu Arg Glu Aβp Gin 115 120 125 CTG CCT CCT GGC TTC CCC AAC ATT GAC ATG GGC CCC CAG TTG AAG GTT 1267 Leu Pro Pro Gly Phe Pro Asn lie Asp Met Gly Pro Gin Leu Lys Val 130 135 140 145 GTA GAG CGC ACA CGC ACA GCC ACC ATG CTC TGT GCT GCC AGC GGA AAC 1315 Val Glu Arg Thr Arg Thr Ala Thr Met Leu Cys Ala Ala Ser Gly Asn 150 155 160 CCT GAC CCT GAG ATC ACC TGG TTC AAG GAC TTC CTG CCT GTG GAC CCC 1363 Pro Aβp Pro Glu lie Thr Trp Phe Lys Asp Phe Leu Pro Val Asp Pro 165 170 175 AGT GCC AGC AAT GGG CGG ATC AAG CAG CTT CGG TCA GGT GCC CTG CAG 1411 Ser Ala Ser Asn Gly Arg lie Lye Gin Leu Arg Ser Gly Ala Leu Gin 180 185 190 ATT GAG AGC AGC GAG GAG ACA GAC CAG GGC AAG TAC GAG TGT GTG GCC 1459 lie Glu Ser Ser Glu Glu Thr.Asp Gin Gly Lys Tyr Glu Cys Val Ala 195 200 205 ACC AAC AGC GCT GGG GTG CGC TAC TCA TCA CCT GCC AAC CTC TAC GTG 1507 Thr Asn Ser Ala Gly Val Arg Tyr Ser Ser Pro Ala Asn Leu Tyr Val 210 215 220 225 CGA GTC CGC CGT GTG GCC CCC CGC TTC TCC ATC CTG CCC ATG AGC CAC 1555 Arg Val Arg Arg Val Ala Pro Arg Phe Ser lie Leu Pro Met Ser His 230 235 240 GAG ATC ATG CCC GGT GGG AAT GTG AAT ATC ACT TGT GTG GCT GTG GGC 1603 Glu lie Met Pro Gly Gly Asn Val Asn lie Thr Cyβ Val Ala Val Gly 245 250 255 TCA CCC ATG CCC TAC GTG AAG TGG ATG CAG GGG GCA GAG GAC CTG ACG 1651 Ser Pro Met Pro Tyr Val Lys Trp Met Gin Gly Ala Glu Asp Leu Thr 260 265 270 CCT GAG GAT GAC ATG CCC GTG GGT CGG AAT GTC CTC GAA CTC ACG GAT 1699 Pro Glu Asp Asp Met Pro Val Gly Arg Asn Val Leu Glu Leu Thr Asp 275 280 285 GTC AAA GAC TCA GCC AAC TAT ACT TGT GTG GCC ATG TCC AGC CTG GGA 1747 Val Lys Asp Ser Ala Asn Tyr Thr Cyβ Val Ala Met Ser Ser Leu Gly 290 295 300 305 GTG ATC GAG GCC GTT GCT CAG ATC ACT GTA AAA TCT CTC CCC AAA GCC 1795 Val He Glu Ala Val Ala Gin He Thr Val Lye Ser Leu Pro Lys Ala 310 315 320 CCT GGG ACT CCC GTG GTG ACG GAG AAC ACT GCT ACC AGT ATC ACT GTC 1843 Pro Gly Thr Pro Val Val Thr Glu Asn Thr Ala Thr Ser He Thr Val 325 330 335 ACA TGG GAC TCA GGC AAT CCT GAC CCT GTG TCC TAC TAC GTA ATT GAG 1891 Thr Trp Asp Ser Gly Asn Pro Asp Pro Val Ser Tyr Tyr Val He Glu 340 345 350 TAT AAA TCC AAA AGC CAG GAT GGG CCG TAT CAG ATC AAA GAA GAC ATC 1939 Tyr Lys Ser Lye Ser Gin Asp Gly Pro Tyr Gin He Lys Glu Asp He 355 360 365 ACC ACC ACG CGC TAC AGC ATC GGC GGC CTG AGC CCC AAC TCT GAG TAT 1987 Thr Thr Thr Arg Tyr Ser He Gly Gly Leu Ser Pro Aβn Ser Glu Tyr 370 375 380 385 GAG ATC TGG GTG TCA GCT GTC AAC TCC ATC GGC CAG GGC CCC CCC AGT 2035 Glu He Trp Val Ser Ala Val Asn Ser He Gly Gin Gly Pro Pro Ser 390 395 400 GAG TCG GTG GTG ACC CGC ACA GGC GAG CAG GCA CCA GCC AGT GCT CCC 2083 Glu Ser Val Val Thr Arg Thr Gly Glu Gin Ala Pro Ala Ser Ala Pro 405 410 415 AGG AAT GTT CAG GCG CGC ATG CTC AGT GCC ACC ACC ATG ATT GTG CAG 2131 Arg Aβn Val Gin Ala Arg Met Leu Ser Ala Thr Thr Met He Val Gin 420 425 430 TGG GAG GAG CCC GTG GAG CCC AAT GGC CTG ATC CGT GGC TAC CGC GTC 2179 Trp Glu Glu Pro Val Glu Pro Asn Gly Leu He Arg Gly Tyr Arg Val 435 440 445 TAC TAC ACC ATG GAG CCC GAG CAT CCG GTG GGC AAC TGG CAG AAG CAC 2227 Tyr Tyr Thr Met Glu Pro Glu His Pro Val Gly Asn Trp Gin Lys His 450 455 460 465 AAT GTG GAC GAC AGT CTT CTG ACC ACT GTG GGC AGC CTG CTA GAG GAT 2275 Asn Val Asp Aβp Ser Leu Leu Thr Thr Val Gly Ser Leu Leu Glu Aβp 470 475 480 GAG ACC TAC ACT GTG AGA GTG CTC GCC TTC ACA TCG GTG GGC GAT GGG 2323 Glu Thr Tyr Thr Val Arg Val Leu Ala Phe Thr Ser Val Gly Asp Gly 485 490 495 CCA CTG TCA GAC CCC ATC CAG GTC AAG ACC CAG CAG GGA GTG CCC GGC 2371 Pro Leu Ser Asp Pro He Gin Val Lys Thr Gin Gin Gly Val Pro Gly 500 505 510 CAG CCC ATG AAC TTG CGG GCT GAG GCC AAG TCA GAG ACC AGC ATT GGG 2419 Gin Pro Met Asn Leu Arg Ala Glu Ala Lys Ser Glu Thr Ser He Gly 515 520 525 CTC TCG TGG AGT GCA CCA CGG CAG GAG AGT GTC ATT AAG TAT GAA CTG 2467 Leu Ser Trp Ser Ala Pro Arg Gin Glu Ser Val He Lye Tyr Glu Leu 530 535 540 545 CTC TTC CGG GAG GGC GAC CGA GGC CGA GAG GTG GGG CGA ACC TTC GAC 2515 Leu Phe Arg Glu Gly Aβp Arg Gly Arg Glu Val Gly Arg Thr Phe Aβp 550 555 560 CCA ACC ACA GCC TTT GTG GTG GAG GAC CTC AAG CCC AAT ACG GAG TAC 2563 Pro Thr Thr Ala Phe Val Val Glu Aβp Leu Lys Pro Aβn Thr Glu Tyr 565 570 575 GCG TTC CGG CTG GCG GCT CGC TCG CCG CAG GGC CTG GGC GCC TTC ACC 2611 Ala Phe Arg Leu Ala Ala Arg Ser Pro Gin Gly Leu Gly Ala Phe Thr 580 585 590 GCG GTT GTG CGC CAG CGC ACA CTG CAG GCC ATC TCC CCC AAG AAC TTC 2659 Ala Val Val Arg Gin Arg Thr Leu Gin Ala He Ser Pro Lys Aβn Phe 595 600 605 AAG GTG AAG ATG ATC ATG AAA ACT TCA GTG CTG CTA AGC TGG GAG TTC 2707 Lys Val Lye Met He Met Lye Thr Ser Val Leu Leu Ser Trp Glu Phe 610 615 620 625 CCT GAC AAC TAT AAC TCA CCC ACG CCC TAC AAG ATC CAG TAC AAT GGA 2755 Pro Aβp Aβn Tyr Aβn Ser Pro Thr Pro Tyr Lys He Gin Tyr Aβn Gly 630 635 640 CTC ACA CTG GAC GTG GAT GGC CGC ACT ACC AAG AAG CTG ATC ACG CAC 2803 Leu Thr Leu Asp Val Aβp Gly Arg Thr Thr Lye Lys Leu He Thr His 645 650 655 CTC AAG CCA CAC ACC TTC TAT AAC TTC GTG CTC ACC AAC CGT GGC AGC 2851 Leu Lys Pro Hie Thr Phe Tyr Asn Phe Val Leu Thr Asn Arg Gly Ser 660 665 670 AGC CTG GGA GGC CTG CAG CAG ACG GTC ACC GCC AGG ACC GCC TTC AAC 2899 Ser Leu Gly Gly Leu Gin Gin Thr Val Thr Ala Arg Thr Ala Phe Aβn 675 680 685 ATG CTC AGT GGC AAG CCT AGT GTC GCC CCA AAG CCT GAC AAC GAT GGT 2947 Met Leu Ser Gly Lye Pro Ser Val Ala Pro Lye Pro Aβp Asn Asp Gly 690 695 700 705 TCC ATT GTG GTC TAC CTG CCT GAT GGC CAG AGT CCC GTG ACA GTG CAG 2995 Ser He Val Val Tyr Leu Pro Aβp Gly Gin Ser Pro Val Thr Val Gin 710 715 720 AAC TAC TTC ATT GTG ATG GTC CCA CTT CGG AAG TCT CGT GGT GGC CAG 3043 Aβn Tyr Phe He Val Met Val Pro Leu Arg Lye Ser Arg Gly Gly Gin 725 730 735 TTC CCT ATC CTA CTA GGT AGT CCA GAG GAC ATG GAT CTG GAG GAG CTC 3091 Phe Pro He Leu Leu Gly Ser Pro Glu Aβp Met Aβp Leu Glu Glu Leu 740 745 750 ATC CAG GAC CTC TCC CGG CTG CAG AGG CGC AGC CTG CGC CAC TCA AGA 3139 He Gin Asp Leu Ser Arg Leu Gin Arg Arg Ser Leu Arg His Ser Arg 755 760 765 CAG CTG GAG GTG CCT CGG CCT TAC ATC GCC GCT CGG TTC TCC ATC CTG 3187 Gin Leu Glu Val Pro Arg Pro Tyr He Ala Ala Arg Phe Ser He Leu 770 775 780 785 CCA GCT GTC TTC CAT CCT GGG AAC CAG AAG CAA TAT GGT GGC TTT GAC 3235 Pro Ala Val Phe His Pro Gly Asn Gin Lys Gin Tyr Gly Gly Phe Asp 790 795 800 AAC AGG GGC TTG GAG CCA GGC CAC CGT TAT GTC CTC TTT GTA CTT GCT 3283 Aβn Arg Gly Leu Glu Pro Gly Hie Arg Tyr Val Leu Phe Val Leu Ala 805 810 815 GTG CTG CAG AAG AAT GAG CCT ACA TTT GCA GCC AGT CCC TTC TCA GAC 3331 Val Leu Gin Lye Aβn Glu Pro Thr Phe Ala Ala Ser Pro Phe Ser Asp 820 825 830 CCC TTC CAA CTG GAC AAC CCA GAC CCG CAG CCC ATT GTG GAT GGC GAG 3379 Pro Phe Gin Leu Aβp Asn Pro Aβp Pro Gin Pro He Val Aβp Gly Glu 835 840 845 GAG GGC CTC ATC TGG GTG ATC GGG CCC GTG CTG GCC GTG GTC TTC ATC 3427 Glu Gly Leu He Trp Val He Gly Pro Val Leu Ala Val Val Phe He 850 855 860 865 ATC TGC ATC GTA ATT GCC ATC CTG CTG TAC AAG AAC AAG CCT GAC AGC 3475 He Cyβ He Val He Ala He Leu Leu Tyr Lye Aβn Lye Pro Aβp Ser 870 875 880 AAA CGC AAG GAC TCA GAG CCC CGC ACC AAA TGC TTA TTG AAC AAT GCA 3523 Lys Arg Lys Aβp Ser Glu Pro Arg Thr Lye Cyβ Leu Leu Aβn Aβn Ala 885 890 895 GAC CTC GCC CCC CAT CAC CCC AAG GAC CCT GTG GAA ATG CGA CGT ATC 3571 Aβp Leu Ala Pro Hie Hie Pro Lye Asp Pro Val Glu Met Arg Arg He 900 905 910 AAC TTC CAG ACG CCA GGT ATG CTC AGC CAC CCG CCC ATT CCC ATC ACA 3619 Aβn Phe Gin Thr Pro Gly Met Leu Ser Hie Pro Pro He Pro He Thr 915 920 925 GAC ATG GCT GAA CAC ATG GAG AGA CTC AAA GCC AAC GAC AGC CTC AAG 3667 Aβp Met Ala Glu Hie Met Glu Arg Leu Lye Ala Aβn Asp Ser Leu Lye 930 935 940 945 CTC TCC CAG GAG TAT GAG TCC ATC GAC CCT GGC CAG CAG TTC ACT TGG 3715 Leu Ser Gin Glu Tyr Glu Ser He Aβp Pro Gly Gin Gin Phe Thr Trp 950 955 960 GAA CAT TCG AAC CTG GAG GCC AAC AAG CCA AAG AAC CGA TAC GCC AAT 3763 Glu Hie Ser Aβn Leu Glu Ala Aβn Lys Pro Lys Asn Arg Tyr Ala Asn 965 970 975 GTC ATC GCC TAT GAC CAT TCA CGA GTC ATC CTG CAG CCT TTA GAA GGC 3811 Val He Ala Tyr Aβp Hie Ser Arg Val He Leu Gin Pro Leu Glu Gly 980 985 990 ATC ATG GGT AGT GAT TAC ATC AAT GCC AAC TAT GTG GAC GGC TAT CGG 3859 He Met Gly Ser Aβp Tyr He Aβn Ala Aβn Tyr Val Aβp Gly Tyr Arg 995 1000 1005 CGG CAG AAC GCA TAC ATC GCC ACG CAG GGG CCC CTC CCT GAA ACC TTT 3907 Arg Gin Asn Ala Tyr He Ala Thr Gin Gly Pro Leu Pro Glu Thr Phe 1010 1015 1020 1025 GGG GAC TTC TGG CGG ATG GTG TGG GAG CAG CGG TCA GCC ACT GTG GTC 3955 Gly Aβp Phe Trp Arg Met Val Trp Glu Gin Arg Ser Ala Thr Val Val 1030 1035 1040 ATG ATG ACA CGG CTG GAG GAG AAA TCA CGG GTC AAA TGT GAC CAG TAC 4003 Met Met Thr Arg Leu Glu Glu Lye Ser Arg Val Lys Cyβ Aβp Gin Tyr 1045 1050 1055 TGG CCT AAC CGA GGC ACC GAG ACA TAC GGC TTC ATC CAG GTC ACC CTA 4051 Trp Pro Aβn Arg Gly Thr Glu Thr Tyr Gly Phe He Gin Val Thr Leu 1060 1065 1070 CTA GAT ACT ATG GAG CTG GCC ACC TTC TGT GTC AGG ACC TTT TCT CTA 4099 Leu Aβp Thr Met Glu Leu Ala Thr Phe Cyβ Val Arg Thr Phe Ser Leu 1075 1080 1085 CAC AAG AAT GGC TCT AGT GAG AAG CGT GAG GTA CGA CAT TTT CAG TTC 4147 Hie Lye Aβn Gly Ser Ser Glu Lye Arg Glu Val Arg Hie Phe Gin Phe 1090 1095 1100 1105 ACA GCA TGG CCT GAC CAC GGG GTA CCC GAG TAC CCC ACA CCC TTC CTG 4195 Thr Ala Trp Pro Aβp Hie Gly Val Pro Glu Tyr Pro Thr Pro Phe Leu 1110 1115 1120 GCG TTT CTG CGC AGA GTC AAG ACC TGC AAC CCG CCT GAC GCT GGC CCA 4243 Ala Phe Leu Arg Arg Val Lye Thr Cyβ Aβn Pro Pro Aβp Ala Gly Pro 1125 1130 1135 GTT GTG GTC CAC TGC AGC GCG GGT GTG GGG CGT ACT GGC TGC TTC ATT 4291 Val Val Val Hie Cyβ Ser Ala Gly Val Gly Arg Thr Gly Cyβ Phe He 1140 1145 1150 GTA ATT GAT GCC ATG TTG GAG CGC ATC AGA ACA GAG AAG ACG GTG GAT 4339 Val He Aβp Ala Met Leu Glu Arg He Arg Thr Glu Lye Thr Val Aβp 1155 1160 1165 GTG TAC GGA CAC GTG ACA CTC ATG CGG TCA CAG CGC AAC TAC ATG GTG 4387 Val Tyr Gly Hie Val Thr Leu Met Arg Ser Gin Arg Aβn Tyr Met Val 1170 1175 1180 1185 CAG ACA GAG GAT CAG TAT AGC TTC ATC CAC GAG GCA CTG CTG GAG GCT 4435 Gin Thr Glu Aβp Gin Tyr Ser Phe He Hie Glu Ala Leu Leu Glu Ala 1190 1195 1200 GTG GGC TGT GGC AAT ACC GAG GTC CCC GCG CGC AGC CTC TAC ACC TAT 4483 Val Gly Cyβ Gly Aβn Thr Glu Val Pro Ala Arg Ser Leu Tyr Thr Tyr 1205 1210 1215 ATC CAG AAG CTG GCC CAG GTG GAG CCT GGC GAG CAT GTC ACA GGA ATG 4531 He Gin Lye Leu Ala Gin Val Glu Pro Gly Glu His Val Thr Gly Met 1220 1225 1230 GAG CTT GAG TTC AAG AGG CTT GCC AGC TCC AAG GCA CAC ACT TCG AGA 4579 Glu Leu Glu Phe Lys Arg Leu Ala Ser Ser Lys Ala Hie Thr Ser Arg 1235 1240 1245 TTC ATC ACT GCC AGC CTG CCT TGC AAC AAG TTT AAG AAC CGC CTG GTG 4627 Phe He Thr Ala Ser Leu Pro Cyβ Aβn Lye Phe Lye Aβn Arg Leu Val 1250 1255 1260 1265 AAC ATC CTG CCG TAC GAG AGC TCG CGT GTC TGC CTG CAG CCC ATT CGT 4675 Aβn He Leu Pro Tyr Glu Ser Ser Arg Val Cyβ Leu Gin Pro He Arg 1270 1275 1280 GGT GTC GAG GGC TCT GAC TAC ATC AAT GCC AGC TTC ATC GAC GGC TAC 4723 Gly Val Glu Gly Ser Aβp Tyr He Aβn Ala Ser Phe He Aβp Gly Tyr 1285 1290 1295 AGA CAG CAG AAA GCC TAC ATT GCA ACG CAG GGT CCA CTG GCA GAG ACC 4771 Arg Gin Gin Lye Ala Tyr He Ala Thr Gin Gly Pro Leu Ala Glu Thr 1300 1305 1310 ACA GAG GAC TTC TGG CGT GCC CTG TGG GAG AAC AAC TCC ACT ATT GTG 4819 Thr Glu Aβp Phe Trp Arg Ala Leu Trp Glu Aβn Aβn Ser Thr He Val 1315 1320 1325 GTA ATG CTC ACC AAG CTC CGC GAG ATG GGC CGG GAG AAG TGC CAC CAG 4867 Val Met Leu Thr Lye Leu Arg Glu Met Gly Arg Glu Lye Cyβ Hie Gin 1330 1335 1340 1345 -66- TAC TGG CCA GCT GAG CGC TCT GCC CGC TAC CAG TAC TTT GTG GTT GAC 4915 Tyr Trp Pro Ala Glu Arg Ser Ala Arg Tyr Gin Tyr Phe Val Val Aβp 1350 1355 1360 CCG ATG GCA GAG TAT AAC ATG CCA CAG TAC ATT CTG CGT GAG TTT AAG 4963 Pro Met Ala Glu Tyr Aβn Met Pro Gin Tyr He Leu Arg Glu Phe Lye 1365 1370 1375 GTC ACA GAT GCC CGG GAT GGC CAG TCC CGG ACC GTC CGA CAG TTC CAG 5011 Val Thr Aβp Ala Arg Aβp Gly Gin Ser Arg Thr Val Arg Gin Phe Gin 1380 1385 1390 TTC ACG GAC TGG CCA GAG CAG GGT GCA CCC AAG TCA GGG GAA GGC TTC 5059 Phe Thr Aβp Trp Pro Glu Gin Gly Ala Pro Lye Ser Gly Glu Gly Phe 1395 1400 1405 ATT GAC TTC ATC GGC CAA GTG CAT AAG ACC AAG GAG CAG TTT GGC CAG 5107 He Aβp Phe He Gly Gin Val Hie Lye Thr Lys Glu Gin Phe Gly Gin 1410 1415 1420 1425 GAT GGC CCC ATC TCG GTG CAC TGT AGT GCT GGA GTG GGC AGG ACC GGA 5155 Aβp Gly Pro He Ser Val Hie Cyβ Ser Ala Gly Val Gly Arg Thr Gly 1430 1435 1440 GTA TTC ATC ACT CTG AGC ATC GTG CTG GAG CGA ATG CGC TAC GAG GGG 5203 Val Phe He Thr Leu Ser He Val Leu Glu Arg Met Arg Tyr Glu Gly 1445 1450 1455 GTG GTG GAC ATT TTC CAG ACA GTG AAG GTG CTT CGG ACC CAG CGG CCT 5251 Val Val Aβp He Phe Gin Thr Val Lys Val Leu Arg Thr Gin Arg Pro 1460 1465 1470 GCC ATG GTG CAG ACA GAG GAT GAG TAC CAG TTC TGC TTC CAG GCG GCG 5299 Ala Met Val Gin Thr Glu Aβp Glu Tyr Gin Phe Cys Phe Gin Ala Ala 1475 1480 1485 TTG GAA TAC CTG GGC AGC TTT GAT CAT TAT GCA ACA TAAGCCATGG 5345 Leu Glu Tyr Leu Gly Ser Phe Asp His Tyr Ala Thr 1490 1495 1500 GCCCCGCCCA ACACCTCGAC CCAGCTCCAA GTGCCCTGAA TGTGAGCCCA GCCCTCGGTG 5405 CTGGGTGGGA GGCGGCCCAG GGAGGAAACC TCCTCTCCCT GGAGACAGGC ACTGCCTTCG 5465 GAAGGGCACA TTCCTCATTC CCTCCTGACT CCAAAACGAG GTTCCAGGGT GGGGGGTAGG 5525 GTGGAGAGTA GAGGAGGCAC TGCTCCCCAT AGCTGGGGTC ACAAGGGACA GAACTCTGCT 5585 CCCACACTTC CCTGCCTGCC TGTCAGCAAC ATTCTTTTTT TCCATTTTTT TAATAGTGTA 5645 TTTTTTTTCT TCATCTTTCT TTTTTTTTTT TAAAAAAAAA AAAAA 5690 (2) INFORMATION FOR SEQ ID NO:3: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 1501 amino acids (B) TYPE: amino acid (D) TOPOLOGY: linear (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3: Met Ala Pro Thr Trp Arg Pro Ser Val Val Ser Val Val Gly Pro Val 1 5 10 15 Gly Leu Phe Leu Val Leu Leu Ala Arg Gly Cys Leu Ala Glu Glu Pro 20 25 30 Pro Arg Phe He Arg Glu Pro Lye Aβp Gin He Gly Val Ser Gly Gly 35 40 45 Val Ala Ser Phe Val Cyβ Gin Ala Thr Gly Aβp Pro Lye Pro Arg Val 50 55 60 Thr Trp Aβn Lye Lye Gly Lye Lye Val Aβn Ser Gin Arg Phe Glu Thr 65 70 75 80 He Aβp Phe Aβp Glu Ser Ser Gly Ala Val Leu Arg He Gin Pro Leu 85 90 95 Arg Thr Pro Arg Aβp Glu Aβn Val Tyr Glu Cyβ Val Ala Gin Aβn Ser 100 105 110 Val Gly Glu He Thr Val Hie Ala Lye Leu Thr Val Leu Arg Glu Asp 115 120 125 Gin Leu Pro Pro Gly Phe Pro Asn He Aβp Met Gly Pro Gin Leu Lys 130 135 140 Val Val Glu Arg Thr Arg Thr Ala Thr Met Leu Cyβ Ala Ala Ser Gly 145 150 155 160 Aβn Pro Asp Pro Glu He Thr Trp Phe Lye Aβp Phe Leu Pro Val Aβp 165 170 175 Pro Ser Ala Ser Aβn Gly Arg He Lye Gin Leu Arg Ser Gly Ala Leu 180 185 190 Gin He Glu Ser Ser Glu Glu Thr Asp Gin Gly Lys Tyr Glu Cys Val 195 200 205 Ala Thr Aβn Ser Ala Gly Val Arg Tyr Ser Ser Pro Ala Aβn Leu Tyr 210 215 220 Val Arg Val Arg Arg Val Ala Pro Arg Phe Ser He Leu Pro Met Ser 225 230 235 240 Hie Glu He Met Pro Gly Gly Aβn Val Aβn He Thr Cys Val Ala Val 245 250 255 Gly Ser Pro Met Pro Tyr Val Lye Trp Met Gin Gly Ala Glu Aβp Leu 260 265 270 Thr Pro Glu Aβp Aβp Met Pro Val Gly Arg Aβn Val Leu Glu Leu Thr 275 280 285 Aβp Val Lye Aβp Ser Ala Aβn Tyr Thr Cyβ Val Ala Met Ser Ser Leu 290 295 300 Gly Val He Glu Ala Val Ala Gin He Thr Val Lye Ser Leu Pro Lys 305 310 315 320 Ala Pro Gly Thr Pro Val Val Thr Glu Asn Thr Ala Thr Ser He Thr 325 330 335 Val Thr Trp Asp Ser Gly Aβn Pro Aβp Pro Val Ser Tyr Tyr Val He 340 345 350 Glu Tyr Lye Ser Lys Ser Gin Aβp Gly Pro Tyr Gin He Lye Glu Asp 355 360 365 He Thr Thr Thr Arg Tyr Ser He Gly Gly Leu Ser Pro Asn Ser Glu 370 375 380 Tyr Glu He Trp Val Ser Ala Val Aβn Ser He Gly Gin Gly Pro Pro 385 390 395 400 Ser Glu Ser Val Val Thr Arg Thr Gly Glu Gin Ala Pro Ala Ser Ala 405 410 415 Pro Arg Aβn Val Gin Ala Arg Met Leu Ser Ala Thr Thr Met He Val 420 425 430 Gin Trp Glu Glu Pro Val Glu Pro Aβn Gly Leu He Arg Gly Tyr Arg 435 440 445 Val Tyr Tyr Thr Met Glu Pro Glu Hiβ Pro Val Gly Aβn Trp Gin Lye 450 455 460 Hiβ Aβn Val Aβp Aβp Ser Leu Leu Thr Thr Val Gly Ser Leu Leu Glu 465 470 475 480 Aβp Glu Thr Tyr Thr Val Arg Val Leu Ala Phe Thr Ser Val Gly Asp 485 490 495 Gly Pro Leu Ser Asp Pro He Gin Val Lye Thr Gin Gin Gly Val Pro 500 505 510 Gly Gin Pro Met Aβn Leu Arg Ala Glu Ala Lye Ser Glu Thr Ser He 515 520 525 Gly Leu Ser Trp Ser Ala Pro Arg Gin Glu Ser Val He Lye Tyr Glu 530 535 540 Leu Leu Phe Arg Glu Gly Aβp Arg Gly Arg Glu Val Gly Arg Thr Phe 545 550 555 560 Aβp Pro Thr Thr Ala Phe Val Val Glu Aβp Leu Lye Pro Aβn Thr Glu 565 570 575 Tyr Ala Phe Arg Leu Ala Ala Arg Ser Pro Gin Gly Leu Gly Ala Phe 580 585 590 Thr Ala Val Val Arg Gin Arg Thr Leu Gin Ala He Ser Pro Lys Asn 595 600 605 Phe Lye Val Lys Met He Met Lye Thr Ser Val Leu Leu Ser Trp Glu 610 615 620 Phe Pro Asp Asn Tyr Asn Ser Pro Thr Pro Tyr Lye He Gin Tyr Asn 625 630 635 640 Gly Leu Thr Leu Aβp Val Aβp Gly Arg Thr Thr Lys Lys Leu He Thr 645 650 655 His Leu Lye Pro Hiβ Thr Phe Tyr Aβn Phe Val Leu Thr Aan Arg Gly 660 665 670 Ser Ser Leu Gly Gly Leu Gin Gin Thr Val Thr Ala Arg Thr Ala Phe 675 680 685 Aβn Met Leu Ser Gly Lye Pro Ser Val Ala Pro Lye Pro Aβp Aβn Asp 690 695 700 Gly Ser He Val Val Tyr Leu Pro Asp Gly Gin Ser Pro Val Thr Val 705 710 715 720 Gin Asn Tyr Phe He Val Met Val Pro Leu' Arg Lys Ser Arg Gly Gly 725 730 735 Gln Phe Pro He Leu Leu Gly Ser Pro Glu Aβp Met Asp Leu Glu Glu 740 745 750 Leu He Gin Aβp Leu Ser Arg Leu Gin Arg Arg Ser Leu Arg Hiβ Ser 755 760 765 Arg Gin Leu Glu Val Pro Arg Pro Tyr He Ala Ala Arg Phe Ser He 770 775 780 Leu Pro Ala Val Phe Hiβ Pro Gly Aβn Gin Lye Gin Tyr Gly Gly Phe 785 790 795 800 Aep Aβn Arg Gly Leu Glu Pro Gly Hiβ Arg Tyr Val Leu Phe Val Leu 805 810 815 Ala Val Leu Gin Lye Aβn Glu Pro Thr Phe Ala Ala Ser Pro Phe Ser 820 825 830 Aβp Pro Phe Gin Leu Aβp Aβn Pro Aβp Pro Gin Pro He Val Asp Gly 835 840 845 Glu Glu Gly Leu He Trp Val He Gly Pro Val Leu Ala Val Val Phe 850 855 860 He He Cys He Val He Ala He Leu Leu Tyr Lys Aβn Lys Pro Asp 865 870 875 880 Ser Lye Arg Lys Aep Ser Glu Pro Arg Thr Lye Cyβ Leu Leu Aβn Aβn 885 890 895 Ala Aβp Leu Ala Pro Hiβ Hiβ Pro Lye Aep Pro Val Glu Met Arg Arg 900 905 910 He Aβn Phe Gin Thr Pro Gly Met Leu Ser Hiβ Pro Pro He Pro He 915 920 925 Thr Aβp Met Ala Glu Hiβ Met Glu Arg Leu Lye Ala Aβn Asp Ser Leu 930 935 940 Lys Leu Ser Gin Glu Tyr Glu Ser He Aβp Pro Gly Gin Gin Phe Thr 945 950 955 960 Trp Glu Hiβ Ser Aβn Leu Glu Ala Aβn Lye Pro Lye Aβn Arg Tyr Ala 965 970 975 Aβn Val He Ala Tyr Aβp Hiβ Ser Arg Val He Leu Gin Pro Leu Glu 980 985 990 Gly He Met Gly Ser Asp Tyr He Aβn Ala Aβn Tyr Val Aβp Gly Tyr 995 1000 1005 Arg Arg Gin Asn Ala Tyr He Ala Thr Gin Gly Pro Leu Pro Glu Thr 1010 1015 1020 Phe Gly Aβp Phe Trp Arg Met Val Trp Glu Gin Arg Ser Ala Thr Val 1025 1030 1035 1040 Val Met Met Thr Arg Leu Glu Glu Lye Ser Arg Val Lys Cys Asp Gin 1045 1050 1055 Tyr Trp Pro Aβn Arg Gly Thr Glu Thr Tyr Gly Phe He Gin Val Thr 1060 1065 1070 Leu Leu Aβp Thr Met Glu Leu Ala Thr Phe Cyβ Val Arg Thr Phe Ser 1075 1080 1085 Leu Hie Lye Aβn Gly Ser Ser Glu Lys Arg Glu Val Arg His Phe Gin 1090 1095 1100 Phe Thr Ala Trp Pro Asp Hiβ Gly Val Pro Glu Tyr Pro Thr Pro Phe 1105 HIO 1115 1120 Leu Ala Phe Leu Arg Arg Val Lye Thr Cyβ Aβn Pro Pro Aβp Ala Gly 1125 1130 1135 Pro Val Val Val Hiβ Cys Ser Ala Gly Val Gly Arg Thr Gly Cys Phe 1140 1145 1150 He Val He Asp Ala Met Leu Glu Arg He Arg Thr Glu Lye Thr Val 1155 1160 1165 Aβp Val Tyr Gly Hiβ Val Thr Leu Met Arg Ser Gin Arg Aβn Tyr Met 1170 1175 1180 Val Gin Thr Glu Aβp Gin Tyr Ser Phe He Hiβ Glu Ala Leu Leu Glu 1185 1190 1195 1200 Ala Val Gly Cyβ Gly Aβn Thr Glu Val Pro Ala Arg Ser Leu Tyr Thr 1205 1210 1215 Tyr He Gin Lys Leu Ala Gin Val Glu Pro Gly Glu His Val Thr Gly 1220 1225 1230 Met Glu Leu Glu Phe Lys Arg Leu Ala Ser Ser Lye Ala His Thr Ser 1235 1240 1245 Arg Phe He Thr Ala Ser Leu Pro Cyβ Aβn Lys Phe Lys Aβn Arg Leu 1250 1255 1260 Val Aβn He Leu Pro Tyr Glu Ser Ser Arg Val Cyβ Leu Gin Pro He 1265 1270 1275 1280 Arg Gly Val Glu Gly Ser Aβp Tyr He Aβn Ala Ser Phe He Aβp Gly 1285 1290 1295 Tyr Arg Gin Gin Lys Ala Tyr He Ala Thr Gin Gly Pro Leu Ala Glu 1300 1305 1310 Thr Thr Glu Asp Phe Trp Arg Ala Leu Trp Glu Asn Asn Ser Thr He 1315 1320 1325 Val Val Met Leu Thr Lys Leu Arg Glu Met Gly Arg Glu Lys Cys His 1330 1335 134 H 0 Gin Tyr Trp Pro Ala Glu Arg Ser Ala Arg Tyr Gin Tyr Phe Val Val 1345 1350 1355 1360 Aβp Pro Met Ala Glu Tyr Asn Met Pro Gin Tyr He Leu Arg Glu Phe 1365 1370 1375 Lys Val Thr Asp Ala Arg Asp Gly Gin Ser Arg Thr Val Arg Gin Phe 1380 1385 1390 Gin Phe Thr Aβp Trp Pro Glu Gin Gly Ala Pro Lye Ser Gly Glu Gly 1395 1400 1405 Phe He Aβp Phe He Gly Gin Val Hiβ Lye Thr Lye Glu Gin Phe Gly 1410 1415 1420 Gin Aβp Gly Pro He Ser Val Hiβ Cyβ Ser Ala Gly Val Gly Arg Thr 1425 1430 1435 1440 Gly Val Phe He Thr Leu Ser He Val Leu Glu Arg Met Arg Tyr Glu 1445 1450 1455 Gly Val Val Asp He Phe Gin Thr Val Lye Val Leu Arg Thr Gin Arg 1460 1465 1470 Pro Ala Met Val Gin Thr Glu Aβp Glu Tyr Gin Phe Cyβ Phe Gin Ala 1475 1480 1485 Ala Leu Glu Tyr Leu Gly Ser Phe Aβp Hiβ Tyr Ala Thr 1490 1495 1500 (2) INFORMATION FOR SEQ ID NO:4: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 92 amino acidβ (B) TYPE: amino acid (C) STRANDEDNESS: unknown (D) TOPOLOGY: unknown (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO: : Pro Val Phe Val Lys Val Pro Glu Asp Gin Thr Gly Leu Ser Gly Gly 1 5 10 15 Val Ala Ser Phe Val Cyβ Gin Ala Thr Gly Glu Pro Lye Pro Arg He 20 25 30 Thr Trp Met Lye Lye Gly Lye Lye Val Ser Ser Gin Arg Phe Glu Val 35 40 45 He Glu Phe Aβp Aβp Gly Ala Gly Ser Val Leu Arg He Gin Pro Leu 50 55 60 Arg Val Gin Arg Aβp Glu Ala He Tyr Glu Cyβ Thr Ala Thr Aβn Ser 65 70 75 80 Leu Gly Glu He Aβn Thr Ser Ala Lye Leu Ser Val 85 90 (2) INFORMATION FOR SEQ ID NO:5: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 93 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: unknown (D) TOPOLOGY: unknown (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5: Leu Gin Val Asp He Val Pro Ser Gin Gly Glu He Ser Val Gly Glu 1 5 10 15 Ser Lys Phe Phe Leu Cyβ Gin Val Ala Gly Aβp Ala Lys Aβp Lye Asp 20 25 30 He Ser Trp Phe Ser Pro Asn Gly Glu Lys Leu Ser Pro Asn Gin Gin 35 40 45 Arg He Ser Val Val Trp Aβn Asp Asp Aβp Ser Ser Thr Leu Thr He 50 55 60 Tyr Asn Ala Aβn He Aβp Aβp Ala Gly He Tyr Lye Cys Val Val Thr 65 70 75 80 Ala Glu Asp Gly Thr Gin Ser Glu Ala Thr Val Aβn Val 85 90 (2) INFORMATION FOR SEQ ID NO:6: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 92 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: unknown (D) TOPOLOGY: unknown (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6: Lye Pro Pro He Aep Leu Val Val Thr Glu Thr Thr Ala Thr Ser Val 1 5 10 15 Thr Leu Thr Trp Asp Ser Gly Asn Thr Glu Pro Val Ser Phe Tyr Gly 20 25 30 He Gin Tyr Arg Ala Ala Gly Thr Aβp Gly Pro Phe Gin Glu Val Aβp 35 40 45 Gly Val Ala Ser Thr Arg Tyr Ser He Gly Gly Leu Ser Pro Phe Ser 50 55 60 Glu Tyr Ala Phe Arg Val Leu Ala Val Aβn Ser He Gly Arg Gly Pro 65 70 75 80 Pro Ser Glu Ala Val Arg Ala Arg Thr Gly Glu Gin 85 90 (2) INFORMATION FOR SEQ ID NO:7: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 91 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: unknown (D) TOPOLOGY: unknown (ii) MOLECULE TYPE: protein (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7: Ser Pro Pro Thr Asn Leu His Leu Glu Ala Asn Pro Asp Thr Gly Val 1 5 10 15 Leu Thr Val Ser Trp Glu Arg Ser Thr Thr Pro Asp He Thr Gly Tyr 20 25 30 Arg He Thr Thr Thr Pro Thr Aβn Gly Gin Gin Gly Asn Ser Leu Glu 35 40 45 Glu Val Val His Ala Aβp Gin Ser Ser Cys Thr Phe Aβp Aβn Leu Ser 50 55 60 Pro Gly Leu Glu Tyr Asn Val Ser Val Tyr Thr Val Lys Asp Asp Lys 65 70 75 80 Glu Ser Val Pro He Ser Aβp Thr He He Pro 85 90 (2) INFORMATION FOR SEQ ID NO:8: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 20 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: unknown (D) TOPOLOGY: unknown (ii) MOLECULE TYPE: DNA (genomic) (ix) FEATURE: (A) NAME/KEY: modified baβe (B) LOCATION: 15 "" (D) OTHER INFORMATION: /mod_base= i /label= N (xi) SEQUENCE DESCRIPTION: SEQ ID NO:8: GAYTAYATYA AYGCNAGYTT 20 (2) INFORMATION FOR SEQ ID NO:9: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 6 amino acidβ (B) TYPE: amino acid (C) STRANDEDNESS: unknown (D) TOPOLOGY: unknown (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:9: (2) INFORMATION FOR SEQ ID NO:10: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 20 baβe pairβ (B) TYPE: nucleic acid (C) STRANDEDNESS: unknown (D) TOPOLOGY: unknown (ii) MOLECULE TYPE: DNA (genomic) (ix) FEATURE: (A) NAME/KEY: modified_baβe (B) LOCATION: 3 (D) OTHER INFORMATION: /mod_baβe= i /label= N (ix) FEATURE: (A) NAME/KEY: modified_baβe (B) LOCATION: 6 (D) OTHER INFORMATION: /mod_baβe= i /label= N (ix) FEATURE: (A) NAME/KEY: modified_baβe (B) LOCATION: 18 (D) OTHER INFORMATION: /mod_base= i /label= N (xi) SEQUENCE DESCRIPTION: SEQ ID NO:10: AYNCCNGCRC TRCARTGNAC 20 (2) INFORMATION FOR SEQ ID NO:11: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 6 amino acids (B) TYPE: amino acid (C) STRANDEDNESS: unknown (D) TOPOLOGY: unknown (ii) MOLECULE TYPE: peptide (xi) SEQUENCE DESCRIPTION: SEQ ID NO:11: Val His Cys Ser Ala Gly 1 5 (2) INFORMATION FOR SEQ ID NO:12: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 50 base pairs (B) TYPE: nucleic acid (C) STRANDEDNESS: unknown (D) TOPOLOGY: unknown (ii) MOLECULE TYPE: DNA (genomic) (xi) SEQUENCE DESCRIPTION: SEQ ID NO:12: TAGACCACAA TGGAACCATC GTTGTCAGGC TTTGGGGCGA CACTAGGCTT 50

Claims: WHAT IS CLAIMED IS: 1. An isolated mammalian receptor-type protein tyrosine phosphatase-σ protein (RPTPσ) or glycoprotein molecule. 2. The molecule of Claim 1, wherein the molecule comprises the amino acid sequence SEQ ID NO:3, shown in FIG. 2(A)-2(G) . 3. A isolated soluble mammalian receptor-type phosphatase-σ polypeptide (RPTPσ) or glycoprotein molecule. 4. The molecule of Claim 3 wherein the molecule comprises from about amino acid residue 24 to about amino acid residue 850 of amino acid sequence SEQ ID NO:3 in FIG. 2(A)-2(G). 5. The molecule of Claim 1 wherein the molecule is a human receptor-type protein tyrosine phosphatase- σ. 6. An isolated nucleic acid molecule comprising a nucleotide sequence encoding the receptor-type protein tyrosine phosphatase-σ protein of Claim 1. 7. The nucleic acid molecule of Claim 6 wherein the nucleotide sequence encoding the receptor-type protein tyrosine phosphatase-σ is the nucleotide sequence SEQ ID NO:2 shown in FIG. 2(A)-2(G). 8. The nucleic acid molecule of Claim 6 wherein the nucleotide sequence encodes the protein having the amino acid sequence SEQ ID NO:3, shown in FIG. 2(A)- 2(G). 9. The nucleic acid molecule of Claim 6 wherein the nucleic acid molecule is a cDNA molecule. 10. The nucleic acid molecule of Claim 6 wherein the nucleic acid molecule is a genomic DNA molecule. 11. The nucleic acid molecule of Claim .6 wherein the nucleic acid molecule further comprises an expression vector. 12. The nucleic acid molecule of Claim 11 wherein the nucleic acid molecule is a plasmid. 13. A prokaryotic host having the nucleic acid molecule of Claim 11. 14. A eukaryotic host having the nucleic acid of Claim 11. 15. A method for preparing the receptor-type protein tyrosine phosphatase-σ protein or glycoprotein of Claim 1, comprising: (a) culturing a host cell capable of expressing the protein or glycoprotein under culturing conditions that permit expression of the protein or glycoprotein; (b) expressing the protein or glycoprotein; and (c) recovering the protein or glycoprotein from the culture. 16. The method of Claim 15 wherein the host cell is a prokaryotic cell. 17. The method of Claim 15 wherein the host cell is a eukaryotic cell. 18. An antibody specific for the protein or glycoprotein of Claim 1. 19. The antibody of Claim 18 wherein the antibody is a monoclonal antibody. 20. A method for detecting the presence of the nucleic acid molecule of Claim 6, in a cell comprising: (a) contacting the cell or an extract thereof with a nucleic acid probe capable of specifically hybridizing to at least a portion of the nucleic acid molecule of Claim 6 under hybridizing conditions; and (b) measuring the hybridization of the probe to the nucleic acid of the cell, thereby detecting the presence of the nucleic acid sequence. 21. A method for detecting the presence of the nucleic acid molecule of Claim 6, in a cell comprising: (a) contacting the cell with nucleic acid primers capable of specifically binding to at least a portion of the nucleic acid molecule of Claim 6 under hybridizing conditions; (b) selectively amplifying at least a portion of the nucleic acid molecule of Claim 6; and (c) detecting the amplified nucleic acid of the cell, thereby detecting the presence of the nucleic acid molecule. 22. A method for detecting in a cell the presence of or measuring the quantity of a receptor protein tyrosine phosphatase-σ protein or 5 glycoprotein, comprising: (a) contacting the cell or an extract thereof with the antibody of Claim 18; and (b) detecting the binding of the antibody to the cell or extract thereof, or measuring the quantity of 0 antibody bound, thereby determining the presence or measuring the quantity of the receptor protein tyrosine phosphatase- σ protein or glycoprotein. 5 23. A method for identifying a ligand that binds the receptor protein tyrosine phosphatase-σ protein or glycoprotein of Claim 1 comprising exposing at least one ligand molecule to the receptor protein for a time sufficient to allow formation of a receptor-ligand o complex, removing non-complexed molecules, and detecting the presence of the molecule bound to the receptor protein. 24. A method for isolating molecules that bind 5 to the receptor protein tyrosine phosphatase-σ protein or glycoprotein of Claim 1 comprising exposing a mixture of molecules to the receptor protein, removing non-complexed molecules, and eluting the molecules bound to the receptor protein to thereby obtain 0 isolated molecules, capable of binding the receptor protein. 25. A method for identifying compounds that modulate the enzymatic activity of the receptor 5 protein tyrosine phosphatase-σ protein or glycoprotein of Claim 1 comprising exposing cells exhibiting the receptor protein to known ligands for a time sufficient to allow formation of receptor-ligand complexes, measuring phosphotyrosine levels within the cells to obtain an enzyme activity level, and comparing the measured enzyme activity level to the enzyme activity level in cells not exposed to ligand. 26. A method of modulating the endogenous enzymatic activity of a receptor protein tyrosine phosphatase-σ protein or glycoprotein of Claim 1 in a mammal comprising administering to the mammal an effective amount of a ligand to the receptor protein to modulate the enzymatic activity. 27. The method of Claim 26 in which the enzymatic activity of the receptor protein tyrosine phosphatase-σ protein or glycoprotein is increased. 8 - The method of Claim 26 in which the enzymatic activity of the receptor protein tyrosine phosphatase-σ protein or glycoprotein is decreased. 29. The method of Claim 26 in which the modulation of receptor protein tyrosine phosphatase-σ protein or glycoprotein enzymatic activity regulates cellular functions comprising differentiation, metabolism, or cell cycle control. 30. The method of Claim 29 wherein the cellular function regulated is a neuronal cellular function. 31. The method of Claim 26 in which the modulation of receptor enzymatic activity regulates cellular behavior comprising contractility or contact inhibition. 32. The method of Claim 31 wherein the cellular behavior regulated is a neuronal cellular behavior. 33. The method of Claim 26 in which the modulation of receptor enzymatic activity regulates abnormal or deleterious processes comprising inflammation, or cellular transformation to a cancerous state. 34. The method of Claim 33 wherein the abnormal or deleterious processes regulated are abnormal or deleterious neuronal processes.

Inventors: SCHLESSINGER JOSEPH, YAN HAI, SCHLESSINGER, JOSEPH, YAN, HAI
Applicants: UNIV NEW YORK, NEW YORK UNIVERSITY
Application year: 1994
Main classification: A61K49
IPC codes: A61K38, A61P25, A61P29, A61P35, C07H21, C07K14, C07K16, C12N5, C12N9, C12N15, C12P21, C12Q1, C12R1, G01N33